Guitar Hero 360 Downloads

How do you download songs for Guitar Hero 3 on xbox 360?

is there a place or website where i could get new songs for guitar hero, xbox 360?

You need to connect the Xbox Live and buy and download the songs using Microsoft Points.
After they will appear on the game’s offline option, then when you connect again you will be able to play them online.

GameSpot’s Guitar Hero 2 Video Review (Xbox 360)