If it is an "interference" engine, the safest bet is every 60K.
As far as I know the grand guru of complete timing belt knowledge is the Gates Corporation and their "Timing belt Replacement Guide":
You can also verify at that site whether you do have an interference engine.
Any "official" intervals can be tricky though as some states apparently have laws about how soon a new car should need "major service" (timing belt counts). Often the "how soon" is legally defined as 100K or so. So a lot of mechanics will tell you 60-80K while a lot of manuals will tell you 105K.