I found some that you may have use for:

http://www.gimp.org/tutorials/
http://www.cubicdesign.com/gimp/
http://empyrean.lib.ndsu.nodak.edu/~nem/gimp/tuts/
http://gimp-savvy.com/

I found those by searching for - "Gimp Tutorials" on google. Try that to get more matches ^^

Edit, congrats to your 500:th post Oblivion.