This project has been talked about for about a year now, and Fox is still saying they want the movie by 2011, but considering the subject matter, it makes sense that they've yet to find a way to make it for a reasonable cost.  I loved the original series, but something tells me that they're going to have to scale back the scope to bring it to the big screen.

From Wikipedia on Cowboy Bebop:

The crew of the spaceship Bebop are a partnership of bounty hunters, called "cowboys", who travel the solar system trying to apprehend bounties. Jet Black is the owner of the Bebop, but has partnered with Spike for his diverse combat skills. Though he is reluctant to admit it, Jet has also come to rely on Spike for companionship in the normally solitary field of bounty hunting.

Most episodes revolve around attempts to bring in a specific bounty. Some of the Bebop's varied targets include small time thugs, gangsters, hackers (known as "net divers" in slang), religious leaders, psychopaths, genetic experiments, mutant creatures and petty thieves. Occasionally the Bebop crews' pasts catch up with them, and the show regularly views the history of the main characters and more general past events, in flashbacks. For example, Spike's past as an assassin for the syndicate appears in a number of episodes.