If you had dust spots, one of the first things you used to have to do is use the Spot Healing brush to get rid of them. But if you haven't tried it yet, getting rid of dust spots on an image has gotten a bit easier as of the release of Adobe Camera Raw 5.2. You can now clean things up as part of the raw conversion process.
Across the top of the Camera Raw window now is an expanded row of tool icons. Pretty much smack dab in the middle is the new Spot Removal tool. There are only a two sliders for Spot Removal, but you are unlikely to need either for removing dust spots. Radius seems useful at first, but there are better way to control this as we'll see shortly. Leave the Opacity slider at 100% since you are unlikely to want to simply fade the spots. Above both of these is a dropdown that labeled Type that allows you to control the tool's mode of operation. The default is Healing which behaves similarly to the Healing brush in regular Photoshop and works well for most situations. The alternative is Clone which will come in handy on those rare occasions when you have a spot near some detail that confuses the Healing mode.
To get rid of a spot, click on the middle of it with your mouse and drag outwards until the expanding dashed circle encompasses the spot. As you do, the Radius slider will set itself to match the radius of the actual circle you have created. To make you feel at home, you can also use the left and right square bracket keys ("[" and "]") to decrease or increase the radius slider. If you notice, the dashed circle that now surrounds your dust spot is colored red to indicate that this is the area being removed in the removal operation. Camera Raw will automatically create the matching green dashed circle when it picks the area used to synthesize what will replace your spot. With the Preview box just above the right-hand corner of the image is checked (it is by default), you will see the results when it does. If you think you can do a better job of picking a replacement area, click on the green circle with your mouse and drag it to where you want it.
The target (red circle) and source (green circle) for each replacement remain connected by a dashed line between them so you can keep track of them, a feature that you will come to find useful if you have a lot of dust spots on the same image. If you want to see your image without all the circles superimposed on top of it, uncheck the Show Overlay checkbox at the bottom left of the options palette.
If you want to start over with dust removal, click on the Clear All button. When you have finished, click on Open Image or Done as usual. Or, if you decide to give up on an image completely, you can always click on Cancel as usual.
One of the few annoyances of digital photography is having to deal with dust spots. Whereas every film image is captured on a clean new frame, a digital camera has only one sensor and it gets used for all your images. If it gets a spot of dust on it, you'll be able to see it. Over and over again. Kudos to Adobe for making the removal of dust spots that much easier.