I just bought it and got a little dissapointed when I looked at the tool bar and it looks the same as photoshop 7.
The differences are subtle at first but there are lots of differences. Basically, it makes things it a bit more user-friendly. For example, in edit>transform you have a few new things such as 'warp' and I think 'perspective' is new as well.
Play around with it. AND, if you are still at a loss, go to youtube.com or deviantart.com (browse: resources>tutorials) where they will show you different things you can do on CS2. You can also go to the website where they show you new features.