OK.  Just started looking at Blender..When I import a car..How do I get to the blender mat/textures that I downloaded and placed in the blender files??

What type of mats/textures are we talking here?  If they're blender materials in a .blend file, you can import them by going to File->append or link, navigate to and click on your blend file, click on material and then the material name, and click on the import button.  If you just want a texture that isn't associated with a material, do the same thing but click texture instead of material.

Guess I didn't say it right..They are blender files..My question is once I have them imported how do I get to them to paint the car?

Attached Link: http://wiki.blender.org/index.php/Manual/Materials_in_practice

1. have the object selected in object mode
2. in the buttons window, go to the materials panel--it's the little button with the ball icon, or F5
3. make sure that the red ball button on the top of the buttons panel is also selected--this is your material panel; the one that looks kinda like bricks or something is the texture panel, which you may want to look at, too.
4. In the links and pipeline box, you may see an 'add new' button or something that says MA: material, something like that.  There will be a little up/down button to the left of that, click it and there will be a list of all the materials in the scene that are available to you.

A BIG thank you for your time and help!