According DL rep in PRG DL is planning to open ATL-PRG v.v. in 2007, no more details about frequency and equipment, but believe will be daily 763. Will CO match it from EWR. I belive everything depends on crutial CSA decision abour new longhaul aircrafts that is supposed to be taken by the end of MAR. There are 2 possibilities on the table (again from very reliable sources - CSA managment) either 332 or nothing and OK will concentrate on Eurpoean flights only.
If it happens, it would definitely not be a surprise, given a) DL's transatlantic expansion, and b) PRG is currently the only Skyteam hub that doesn't have nonstop service to ATL, so that is a gap that has yet to be closed.