Just to share from my own experience rootofallevil, I've been in the 'I can do the graphics if someone wants to do xml' quiet a few times! Even offered $200 to someone for doing the xml! I was thinking it was as easy as sending a guy a all the images, and he does the xml. Not at all! Once I sent the images and the xml was started, I found out I didn't have half the images & all the images I have already done I removed, edited, or completly changed!
Thats just the graphics part, on the xml side it helps soooo much to know the basics. I have saved my friend a lot of time by doing some basic xml edits on my part, and I enjoy the challenge of xml and learning (I just wish I had more time!)...
Anyway, just wanted to tell ya it helps a lot knowing xml, and remember that most your images you will probably edit more and more and more...
Good luck, stay motivated cause this skin is a great idea