A press release from the National Archives says Antrim, Down and Kerry will launch at 6pm this evening.
There's also a bit more info on future 1911 releases:
Donegal, Cork, Wexford, Galway and Offaly (King's) will be released in March. Monthly releases will follow, with several counties in each batch, until July when all of 1911 should have been released.
1901 will then follow.
I'm told that 1901 will probably be released in one fell-swoop, rather than county by county as originally planned.