I collected the soundtrack based on this url:
http://en.wikipedia.org/wiki/Guitar_Hero_DS

Some of the songs have poor quality but I hope we could collect from everyone's supply of mp3s and come up with a soundtrack with good quality songs.

These are from days of googling and downloading mp3s and contains all the songs listed in Wikipedia.

EDIT:
REUPLOAD: http://qshare.com/get/241617/guitarheroontour.tar.bz2.html

Winrar/Winzip can handle TAR BZ2 packages, don't worry. :)
** Keeping this just incase.

http://www.megaupload.com/pt/?d=GRS9MZA1 <- Doesn't seem to work.