Expect a Worms update shortly, and maybe some DLC shortly thereafter, with a member from the Team 17 development team, Martyn Brown, posting some of the details on his site.
The update is just being finalized now, and then needs to go through the Microsoft certification process before it will be available to download from Live. The main issue it fixes is 4 player games crashing, although apparently this can be fixed somewhat if the host waits for 10-20 seconds until the audible 'beeps' of other players trying to join stops.
Brown also notes the following:
We've also fixed a couple of exploitation issues that have been brought to our attention and also a couple of silly things that crept through the testing net. I'll post a full list when the update goes live (I don't wish to point out some of the exploits!).
Downloadable content is coming soon too, the first lot should include a new theme, a bunch of audio we couldn't fit into the 50mb limit (present at the time we did Worms and recently raised to 150mb), a stack of additional voice-banks and the usual themes & gamer-pics.
By the way, we've had people grumbling about the word-filter on the game, we'd like to point out that this is Microsoft's not ours! :-)