You can often find technical specs for TV shows and movies at http://www.imdb.com. Look for the "technical specs" link on the left-side menu under "Other Info."

A few examples... IMDB lists "Alias" as being shot on 35mm, along with "The X-Files" and "The Sopranos."

These days, I know some shows are shot on 16mm, and Hi-Def is also becoming popular for TV production. The first season of "Buffy" was shot on 16mm, and it seems like I read "Gilmore Girls" shoots on 16mm, also.

-Chance