That's funny because it doesn't say you edited your post... So i'm guessing you just bumped it. Anyways use Photoshop or Gimp. Though Photoshop is the best.
Photoshop is the best, but if you want to obey the law and buy it for $800 but you can't afford it, go with GIMP i hear its pretty good for freeware.
I had to work day and night for it and its worth every penny. After/if you get Photoshop try out a few tuts and get some good brushes from this site.
photoshop cs is the best for me, its easy to use and go look at some big lists, they can teach you everything u need ot konw
get photoshop and dont say you made 2 posts by error and edited,coz you didnt edited you just obvsouly wanted a higher posts count or 1 cred? LOL
The most popular programs are Photoshop but thats cost a load, also the GIMP is ok and free but no where near as good as PS