So where can i get a good quality (or official) soundtrack for New Vegas?
Is there a place where i can get atleast the main menu song?

If you have it on PC, you could probably just rip them in your music library.

If you have the PC version, you get all the music. Since it's 30+ songs total and you'd pay $1 each on itunes, the argument can be made that the PC version doubles as a fairly cheap CD (since the game is only $20)

If you have itunes just go to the music files of the game and double click each song, they automatically play through itunes and are thus added to your library.

Do a search on You tube?

My thoughts exactly, pretty much works for any official soundtrack.

Except Halo 3, every time I looked for that I just got real crazy guitar solos.