where can i find a plugin to view .tga files in windows explorer?

Did you even try Google? It took me all of three seconds to type your own topic title into Google and get results.

i did, i instaled the one form http://greggman.com/pages/thumbplug_tga.htm and it doesnt work, could it be that i am running win vista 64?
it worked when i was using 32 bit

There are a bunch of posts that mention how it doesn't work for 64-bit Windows (discovered by simply adding "64 bit" to the original search).

Still, your Google-fu is weak, because I looked at some of the first few links and came up with multiple potential solutions:
(Read this thread):http://boards.polycount.net/showthread.php?t=56159