You can use the Adobe DNG Converter to convert your raw files to DNG (which is just another type of raw file) and then process them in CS2. I'm pretty sure you can also use Adobe Camera Raw, which comes with CS2 to preprocess the DNG files, adjusting tone and colour balance before taking them into CS2 for any layer and masking work, then export to JPEG.
But there are probably as many photographers using Lightroom as there are using Photoshop CS, and many of us use Lightroom on here so you would never be short of help if you need it. And once you've done your initial corrections in Lightroom you can then pass a photo into CS2 for further editing and when you save it the editing in CS2 will show up back in LR. This is the preferred method for most photographers, I think.
You didn't say what camera you're using but I know that Canon DSLRs come with Digital Photo Professional on the accompanying CD and that's a pretty good piece of software for processing raw files.
If you're shooting Nikon then you'll have ViewNX on the CD which isn't as fully-featured as any of the others I've mentioned but can be used to do tone and colour correction work.
