PC software (in no particular order):

MilkShape 3D : low-poly modeler, $20 (try it for free for 30 days)
UVMapper : uv-mapping tool, freeware and retail ($49.95) versions, demo available
Ultimate Unwrap3D : another UV-mapper, $29 (demo available)
Morph Manager 4.0 : freeware
EditPad Lite : text editor, freeware
P3dO Explorer : file management and thumbnail editing, freeware
Paint Shop Pro : image editing and conversion, ~$100
Crossroads 3D : 3D file conversion, free