Any tips for living cheaply in SF?
dmolnar: Suggest working on how you're going to meet people now -- figure out which events you'll want to go to, which places to hang out, etc. That will help with contacts, which in turn should help with picking up consulting or a formal internship. You can then use this to help plan where you want to live and whether you need a car. Also, as pointed out in the thread, some venues are regrettably 21+.In particular, a lot of events happen on the peninsula in the Palo Alto/Mountain View area. For example, SuperHappyDevHouse is something you probably want to attend, and it's recently been at places like Sun. While getting there by CalTrain is possible, you can't stay late without being badly stranded. So if you find yourself wanting to visit places in that area, you will want access to a car. Bringing your own is an option, there's also car sharing services like ZipCar or CityCarShare.You might also find it fun to drop by Noisebridge, a hacker space near 16th and Mission, to see what's happening. Circuit hacking every monday! 
http://www.noisebridge.net
(disclosure: I'm the secretary and a member)Overall, you are not crazy, but do some prep work by reaching out to potential contacts, setting up meetings, and figuring out the right events now. While the Bay Area _is_ the kind of place where you can walk into a cafe, meet someone random, and then walk out with an incredible conversation that leads to your next opportunity, you will get a lot more out of your summer if you work it ahead of time. Posting here is a good start, but you probably want to do some investigation more closely targeted to your web project idea.