TV.COM has something interesting at
this link.You'll find listed by the major networks (1) the renewed tv shows, (2) the new ones with a brief description, and (3) the canceled/ending shows. It even allows you to vote on each (eg, for canceled shows you can vote "Glad it's gone" or "Please don't go" :) ).
There's a schedule at the bottom of each list, too.
I spotted a new sitcom that interests me. THE IT CROWD, based on a British comedy. When I worked in IT, my life did seem like a sitcom. It won't start until Jan 2008, however.