Welcome from KY.
Insignia is right on. I have CS3 at home and CS4 at work and for most things I do, there's not a huge difference (yes, the cosmetics are different).
http://psd.tutsplus.com/ is a great site full of tutorials but if you need to know the difference in a polygonal lasso and the dodge tool before you start there. If you are just starting in Photoshop, the dummy type books are good or Lynda.com (subscription site) is great is you want to invest in a full gamut of tutorial videos.
Finally, on the project you are working on, it is hard to tell what help you need from your post. Let us know your experience with Photoshop or more detail about what specifically you are having trouble with, and also it might help for you to show a sample/reference image of what you are trying to create or the look you are going for. Good luck.
Allen