I don't think there is an easy way to download tones for the SJ. (if I am wrong someone will correct me)

Check out Joe Gilespie's web site

http://www.joesjamblog.com/index.html

lots of great info there

check out these  pages on tones

http://www.joesjamblog.com/tones.html

http://www.joesjamblog.com/tones4.html

http://www.joesjamblog.com/customtones.html

as for tracks, you can find many many guitar backing tracks on the internet just by searching.

Once you downlooa a backing track you must convert it to a mono wav file, save it to an SD card and you are ready go

Check out Joe's info on this at these pages

http://www.joesjamblog.com/itunes.html

http://www.joesjamblog.com/tips5.html

as you can see there is a wealth of info on Joe's site. (thanks Joe!)

Also, search this forum, lots of good info already here on what you are asking

Hope that helps and above all - Have Fun!!

Steve