I am just starting out so I cannot report with any expertise, but I am currently working with the following:
The Classical Tibetan Language
Beyer, Stephan V.,
State University of New York Press, c1992.
Tibetan Language Correspondence Course
by Sarah Harding and Jeremy Morelli
I Tunes U has a couple of intro courses from Emory University with Tzepak Rigzin
Also, a really fantastic blog:
http://jigtenmig.blogspot.com/search/label/Introduction(some of the links are dead in the earliest posts, but there are a lot of resources listed)
Shaun
