We're just in the process of nailing down the venue, but aiming for the end of May / start of June (essentially once we've managed to do some more testing and integrate some new data sources).

Without giving too much away (I'll get shot by the press team!), its a single API covering all modes of travel in London and surrounding areas, mostly for the first time, think fares, enhanced accessibility options, geodata etc.

Drop me a mail and I'll get you on the invite list if your interested.