Gimpshop...easier migration from photoshop

http://plasticbugs.com/?page_id=294

excerpt from the page...

My original purpose for GIMPshop was to make the Gimp accessible to
the many Adobe Photoshop users out there. I hope I've done that. And
maybe along the way, I can convert a Photoshop pirate into a Gimp
user.

If you've never used Photoshop before, you may not appreciate my
GIMPshop hack. What I've done is renamed and reorganized GIMP's tools,
options, windows, and menus to closely resemble Adobe Photoshop's menu
structure and naming conventions. Many of the menu options and even
whole menus were recreated to faithfully reproduce a Photoshop-like
experience. After running my GIMPshop hack, you'll find that Photoshop
and the GIMP are strikingly similar.

Longtime Photoshop users should feel very comfortable using GIMPshop.

GIMPshop is by no means a 1-to-1 copy of Photoshop and you may find
some menu items that are not in perfect order. But GIMPshop's pretty
close, and I think it does the job. I'm getting lots of use out of it
and I hope you do too.