The strike is not over and doesn't look like it's reaching its end anytime soon. Everyone who isn't David Letterman and Craig Ferguson that are returning are doing so without writers. Leno and Conan O'Brien are members of the guild themselves, and therefore barred from writing monologues. They can improv and that's the extent of it. Expect lots guest focus, assuming people will want to go on the shows (since it could be viewed as them not being supportive of the strike). The Daily Show and the Colbert Report are also supposed to be coming back, but I don't know what the hell they're gonna do with no writers. I think Jimmy Kimmel may also be coming back. A lot of these people are getting desperate and if they don't come back, virtually all of their non-writing staff will be jobless. If Letterman's deal comes through, he and Ferguson (since his show is owned by the same company, Worldwide Pants) will be the only two that return with writers.
Expect schedule changes in the next year as networks scramble for new material to air. Some shows will be leaving the schedule entirely (on what is supposed to be a temporarily basis) as a result.
EDIT: Corrected a mistake.
Also, it is done:
Letterman And Writers Strike Deal, Giving CBS The Edge