The next one's already being prepared for launch:

"Richard McKinney, Air Force undersecretary for
space programs, says the second test X-37B –
OTV-2 – is being prepared in Boeing’s California
space facilities for transfer “soon” to Cape Canaveral.
From there it will be launched on an Atlas V in the
March-April 2011 time period."

See:

http://www.aviationweek.com/aw/gener...paredForLaunch