Migration from Photoshop to GIMP
A lot of amateur and professional photographers use Adobe Photoshop for their image editing needs. For most amateurs, this is like cutting bread with a surgery-steel scalpel, where an ordinary bread-knife would have done more than well enough. That said, it is the standard for most professionals (and aspiring professionals).
As part of my migration to Ubuntu as my primary operating system at home, I'm delighted to find that GIMP actually does pretty much everything Photoshop does - and for free.
Check out The Gimparoo blog for GIMP tutorials for common photo tasks (found via the Ubuntu blog).
Even Windows users can download and use GIMP for free. And if you're a hard core Photoshopper unwilling to switch, you can even continue to use your favourite software after switching to Ubuntu!