I need help with this. Im making a TIE Fighter Model for fun but me and my friend (who is also making one) cant figure out how to paint/add material to selected parts. I already have one material setup for the UV Mapping of the wings, now i need more materials to apply to different parts and faces for windows, body, etc. After i sleect the parts i want to change the color on how to i apply a new material to them without effecting the entire model? Thanks!
here’s a nice tut for ya! 
http://feeblemind.homeip.net/dotclear/index.php/2004/12/21/5-blender-indices-materiau---material-indice
I tried doing what the tutorial said but when i click new with the face i want selected it stays as 1 Mat: 1 and it wont change. Any ideas.
texture paint
select it above face select then in edit buttons select the color size etc did you find it? :o
Doug89, re-read the tutorial! It says add new material - that way you create Mat 2. I had a bit of trouble in the beginning with ‘Assign’ and kept converting my whole model to the new colour. Once you’ve worked it out, you will see how simple it actually is. Plus it is very handy to know. Good luck