Perfect World's CFO stated in an earnings call on Monday that STO will be adopting the "free-to-play" model by the end of the year.
Kelvin Lau wrote:
And also Star Trek Online, after the acquisition, in fact Cryptic is working on the free-to-play model for Star Trek Online. This is going to be launched by the end of this year as well.
You can see the transcript for yourself here
, and I found it via this thread
on the STO official forums. Another user over there also pointed out that one can listen to the audio of the conference call here