There has been rumors about that for a few years now, but Honda is VERY good at keeping secrets until the last minute. Many signs do point to the possibility of '06 being the last year, BUT.... they had to update a bunch of stuff for new emissions laws in '06, strange if they just planned to discontinue it... BUT... the problem is, the 1000RR kicks its ass all over the place on the track, so sales have dropped significantly...
It really could go either way, but history shows that Honda generally goes where the demand is, and there hasn't been that much demand for RC51's lately...