http://www.channel4.com/4talent/national/opportunities/schemes/specific/comingup.html
This looks quite an interesting opportunity, although it seems a bit mean to only allowe people to enter if they've wriiten for a long running series.
Coming Up
You don't actually need to have written for a series. You just need to demonstrate that you've managed to get your career off the ground, and they seem reasonably flexible as to what that might entail.
I was lucky enough to get on the 2007 scheme - never had a broadcast credit before, just commissioned scripts in development and a one act play to my name.
Its a brilliant scheme as well, run by a very supportive team. You get to work with a top cast and learn a lot about the production side of things as well. The films are given an industry screening at the NFT, circulated on DVD to producers and agents, and I had a lot of meetings as a result. They also get broadcast on Channel 4 later in the year, in a better slot this Autumn apparently.
If I'm gushing about it its because I had a great time and its given my career, such as it was, a real boost. Not enough to give up the day job or anything, but welcome all the same.