Hi Hopefull,
I have the same camera and learning as you are. I got a CD with mine "Digital Photo Professional" This is a canon program that I assumed all new Canon's came supplied with. After you download using EOS utility "on the same CD from memory" the editing program lets you adjust things in raw as well as jpeg. I have been using it for a while now to see what all the adjustments do. It is much more limited than Photoshop but there is enough to keep you busy for a while in any case, before you purchase a much more powerful and complex program. You can save RAW & Jpeg in the 550D. And then in Digital photo Professional you set the preferences to see one or the other format or both I think. I always shoot raw even though I am useless at editing but my thoughts on this are that I have ever learnt anything that I didn't try. There are also plenty of things that I never learnt but did try, but thats any story.
If you didn't get the CD with your camera it may be on Canon's website. Worth a try at least

Cheers Kieran