Most of the links I listed up here have already appeared in the tutorial itself. Anyway I wanted to put up a complete listing so here it is.

Drive Ins

• The official Re-Volt Homepage
• The Re-Volt Headquarters with cars & tracks
• The Forum at Racers Point
• The Re-Volt Track Club with some useful tools

Graphic Software

• Photoshop
• Photo Paint
• Paint Shop Pro
• Bryce (3D software)
• Universe Image Creator
• Kai's Power Tools (Filter collection for Photoshop)
• Alien Skin Software (Filter collection for Photoshop)

Texturing

• The Texture Studio with over 400 textures
• ACD See (Image viewer)

Tutorials

• The Photoshop Resources Page
• Creating Custom Cars by RiffRaff

Other tools

• Winzip
• HyperSnap DX (Screenshot tool)