There’s some confusion over this matter (even myself is confused) and the answer is:
- If you own Flash 8 or Studio 8, then you can use it for a long time
- If not, then it is a 30-day trial
Honestly speaking, I don’t think Adobe has made it clear on the website. Tho Mike Downey mention that it is in the FAQ, I wonder how many people will really go and read it (and the FAQ button seems not obvious at all).
It’s better for Adobe to make it clear on the first page of the preview release site.