Well pretty much all of the tut can be done on both Photoshop and Gimp, although the majority have been done on Photoshop.
You can still use the photoshop tut's on gimp, but some of the direction may not make sense, as the layout is different and gimp does not have some filters photoshop has.
This is the only one i could find that was done specifically for gimp by Q.
http://www.whforumsonline.com/forums...ead.php?t=7220