I've been hearing a lot of rumors. The main one floating around is a truncated season 7 of 12 episodes after the writers strike ends then a full season 8 in 2009. Sadly we haven't seen an end to the writers strike so who knows when this is going to happen. My guess is a truncated season 7 in the fall and maybe a full season 8 started jan/feb 2009.
I've heard eight episodes are shot and waiting when the writers strike started fox stated they wanted to go uninterrupted so who knows what is going to happen.