user2075: Question says it. I spent 20 mins Googling. Saw several links on bitcointalk.com but amazingly found no solution to this. Am I the first one trying to do this? 
Note the following are not the solutions I am looking for:

Transfer the BTC from Bitcoin-qt to Multibit by making a transaction
Some commandline geeky stuff


user888: It does not answer your question of getting your private keys out of bitcoin-qt, but this link explains how you import a single private key into MultiBit:
http://multibit.org/help_importASingleKey.html
If you have more than one private key it is simply more rows in the import file.
The date alongside each key is a bit non-obvious. It has to be before the date of the first transaction using that key so that the blocks with the transactions in can be found. I recommend just finding the first transaction in your wallet and putting the date one day before it in on every row. (Using a day earlier avoids any time zone problems).
Note that the import only knows about the sipa format private keys (the ones beginning with a 5). It does not understand compressed keys. ( What is a compressed Bitcoin key? )

user-1: Here is one way to do it without the "command line geeky stuff". 

Visit https://blockchain.info/wallet/import-wallet. Drag the Bitcoin-Qt wallet.dat file into the dotted area. Follow the instructions.
Login to the new wallet. Under the Backup heading click download.
Open multibit choose Tools -> Import Private Keys. Now import the wallet.aes.json file just downloaded.
Delete the keys from the blockchain.info wallet.

However since the goal isn't to setup a blockchain.info wallet you would be much better off using pywallet https://github.com/jackjack-jj/pywallet to dump the wallet and the keys directly.

user6375: Manual Steps

Copy your public receiving addresses from Bitcoin-Qt.
Go to the Bitcoin-Qt console: click Help/Debug Window and then select the Console tab.
Run walletpassphrase [your password] [timeout in seconds] to unlock your password protected wallet.
Run dumpprivkey [Receiving Bitcoin Address] for each receiving address to be migrated to MultiBit. There may be hidden private change addresses in Bitcoin-Qt which don't show up in the receive tab. Run listaddressgroupings.
Copy the results of dumprivkey for each address (which are the corresponding private keys).
Start the Multibit client and create a new wallet.
Click Tools/Export Private Key after selecting the Do not password protect export file option.
Open the exported file in a text editor.
Below the private key generated by MultiBit, paste the private keys you have copied above. Remember to paste them before the End of private keys line.
After each private key, add a date that is prior to when you created the corresponding wallet. (You can check this date in the Bitcoin-Qt Transactions tab and scrolling to the very bottom.)
Repeat for all addresses you want to move to Multibit Client.
Save the key file and import it to the Multibit client using Tools > Import Private Keys.
In MultiBit, you may not see your total until you click Tools > Reset Blockchain and Transactions
In order to protect yourself from theft, delete the private key files.
Done!


2075: <p>Question says it. I spent 20 mins Googling. Saw several links on bitcointalk.com but amazingly found no solution to this. Am I the first one trying to do this? 
Note the following are <strong>not</strong> the solutions I am looking for:</p>

<ol>
<li>Transfer the BTC from Bitcoin-qt to Multibit by making a transaction</li>
<li>Some commandline geeky stuff</li>
</ol>
 888: <p>It does not answer your question of getting your private keys out of bitcoin-qt, but this link explains how you import a single private key into MultiBit:</p>

<p><a href="http://multibit.org/help_importASingleKey.html" rel="nofollow noreferrer">http://multibit.org/help_importASingleKey.html</a></p>

<p>If you have more than one private key it is simply more rows in the import file.</p>

<p>The date alongside each key is a bit non-obvious. It has to be before the date of the first transaction using that key so that the blocks with the transactions in can be found. I recommend just finding the first transaction in your wallet and putting the date one day before it in on every row. (Using a day earlier avoids any time zone problems).</p>

<p>Note that the import only knows about the sipa format private keys (the ones beginning with a 5). It does not understand compressed keys. ( <a href="https://bitcoin.stackexchange.com/questions/3059/what-is-a-compressed-bitcoin-key">What is a compressed Bitcoin key?</a> )</p>
 -1: <p>Here is one way to do it without the "command line geeky stuff". </p>

<ul>
<li>Visit <a href="https://blockchain.info/wallet/import-wallet">https://blockchain.info/wallet/import-wallet</a>. Drag the Bitcoin-Qt wallet.dat file into the dotted area. Follow the instructions.</li>
<li>Login to the new wallet. Under the Backup heading click download.</li>
<li>Open multibit choose Tools -> Import Private Keys. Now import the wallet.aes.json file just downloaded.</li>
<li>Delete the keys from the blockchain.info wallet.</li>
</ul>

<p>However since the goal isn't to setup a blockchain.info wallet you would be much better off using pywallet <a href="https://github.com/jackjack-jj/pywallet">https://github.com/jackjack-jj/pywallet</a> to dump the wallet and the keys directly.</p>
 6375: <h2>Manual Steps</h2>

<ol>
<li>Copy your public receiving addresses from Bitcoin-Qt.</li>
<li>Go to the Bitcoin-Qt console: click <code>Help/Debug Window</code> and then select the <code>Console</code> tab.</li>
<li>Run <code>walletpassphrase [your password] [timeout in seconds]</code> to unlock your password protected wallet.</li>
<li>Run <code>dumpprivkey [Receiving Bitcoin Address]</code> for each receiving address to be migrated to MultiBit. There may be hidden private change addresses in Bitcoin-Qt which don't show up in the receive tab. Run <code>listaddressgroupings</code>.</li>
<li>Copy the results of <code>dumprivkey</code> for each address (which are the corresponding private keys).</li>
<li>Start the Multibit client and create a new wallet.</li>
<li>Click <code>Tools/Export Private Key</code> after selecting the <code>Do not password protect export file</code> option.</li>
<li>Open the exported file in a text editor.</li>
<li>Below the private key generated by MultiBit, paste the private keys you have copied above. Remember to paste them before the <code>End of private keys</code> line.</li>
<li>After each private key, add a date that is prior to when you created the corresponding wallet. (You can check this date in the Bitcoin-Qt <code>Transactions</code> tab and scrolling to the very bottom.)</li>
<li>Repeat for all addresses you want to move to Multibit Client.</li>
<li>Save the key file and import it to the Multibit client using <code>Tools &gt; Import Private Keys</code>.</li>
<li>In MultiBit, you may not see your total until you click <code>Tools &gt; Reset Blockchain and Transactions</code></li>
<li>In order to protect yourself from theft, delete the private key files.</li>
<li>Done!</li>
</ol>
