well, the textures are mostly made in photoshop, right agentxi?
So you would make a model in lets say maya, export the wireframes(UV-mapping) to a picture, and use that picture as a reference in photoshop to create your aplha, bump, displacement, color and so on maps!!
Hope this helps a bit, if you want to make you're own textures you should search down the 3D-forum part because there is a thread somewhere with some answers in it
and offcourse if you need help ask agentxi!!
(
) and if he doesn't know, well you could ask me but I doubt I know more about 3D than agentxi!!