The Mobile Web 2.0 Summit, organised by Osney Media, takes place in London from 3 4 June at the Jumeirah Carlton Tower Hotel in London.
The event features more than 60 speakers, and an impressive line-up it is too, including, among others, the venerable Helen Keegan; Daniel Appelquist, Senior Technology Strategist at Vodafone; Paul Berney, Managing Director, Europe for the MMA; Mark Curtis, CEO of Flirtomatic; and Barry Houlihan CEO of Mobile Interactive Group. 
The organisers have slashed the price of registration for developers from 1,299 (1,140) to 399. Developers also have a chance to win 5,000 worth of premium product placement on the GetJar website in the Developers Den competition. Also at the event, the winner of the 20,000 cash prize for the Betavine Widget competition will be announced. The winner will also have their widget promoted to users in one of Vodafones major markets. Two further prizes of 1,000 will be awarded to Runners Up in the competition.  
Theres more information about the event here. And pricing details here.