Kyle, I'm not too familiar with PSP, but from what I hear it has all the basic functionality of PS (sans stuff like content aware).
It's the PSP interface that gets me. It looks very much like PS, but nothing seems to work the same.
If I were to recommend anything if you want to begin taking post-processing seriously, either Elements (a crippled version of PS) or Lightroom (professional RAW and workflow tool).
Those are both reasonably priced on amazon. If you know anyone who is a teacher or student, you can get some nice discounts on Adobe software.
I'm more than willing to show you the ropes in photoshop.