OK, so we still have quite some time to wait, but it's two months fewer than we thought!
Season 7 of "24" won't be broadcast until January 2009 because of the Writers Strike, but a two-hour stand-alone movie set and shot in South Africa will be broadcast on Sunday, November 23, 2008 from 8-10pm. The movie will be in real time just like the regular show, and the events of the movie take place a couple months before the events of season 7, which will take place in Washington, D.C.
Here's a story with more info.
What a nice pre-Thanksgiving treat!