Here is a list of several free for home/personal use photo editing programs. There are many free programs available, a Google search returns a lot of hits. These have been favorably mentioned by users on other photography sites. The only one I have experience with is Irfanview, I don't about the others.
Some of these include RAW converters, and the features vary significantly between them. As an example, Gimp is pretty well known. The author of Gimp Shop rewrote the user interface to make it more like Photoshop.
IrfanView
http://www.irfanview.com/
Gimp
http://www.gimp.org/windows/
Gimp Shop
http://plasticbugs.com/?page_id=294
Serif Photo Plus 6
http://www.freeserifsoftware.com/
FastStone
http://www.faststone.org/FSViewerDetail.htm
Picasa
http://picasa.google.com/
Paint.net
http://www.getpaint.net/index2.html
VCW VicMan's Photo Editor
http://www.vicman.net/vcwphoto/index.htm