no, you have to make the 3d mesh into a 2d representation (or misrepresentation as the case may be! ) of the mesh. You then export this as a image file and bring it into photoshop etc. Once you've painted it then it will map straight back onto your model in Maya (assuming you dont change the model).

Look on the web for basic uv mapping tutes, there may even be a free video one here O'm not sure.

Failing that goto mike's site and look at the one there. www.mtmckinley.net

It's hard to master this process but you'll get the hang of it eventually.

Alan