Jesse Keating announced on fedora-announce-list:

Due to needing some more time for new features to mature a bit before we
cut our Beta, we've decided to move the Beta release date back to
Tuesday Sept 30th.

This move, combined with previous schedule slips has also driven us to
extend the rest of the Fedora 10 schedule dates by a week, resulting in
a final release date of Tuesday Nov. 25th.

For full schedule information, please see

https://fedoraproject.org/wiki/Releases/Schedule