The atmel data sheet I found,
This Crystal Oscillator is a full swing oscillator, with rail-to-rail swing on the XTAL2 output. This is useful for driving other clock inputs and in noisy environments. ..."
So, yeah, run it in full-swing mode, and it's a TTL clock.
Before I do the rest of your homework for you, Why don't you go ahead and take a look at the other data sheets involved? I'm tempted to guess that the answer to your next question is, "Pull-up", but I wouldn't want to give you a bum steer, and looking up that Atmel clock spec for you just wore me out. Especially that 3 volt stuff - that's like interstellar travel to a well-digger like me. :-)
Good Luck! Rich