From Sky News.
Budget - March 24th
Gordon Brown to Palace - April 6th
Parliament Dissolved - April 8th
Election Launch - April 12th
ITV Debate - April 15th
Sky TV Debate - April 22nd
BBC TV Debate - April 29th
Election Day - May 6th
That seems entirely reasonable, although I would just say that Gordon Brown to palace and Election Launch are in effect the same thing (as the media are not going to wait 48 hours to roll out their election buses and other whatnots). You could also add that in about the middle of April, the manifestos will be launched and that from April 8th - May 6th BBC Parliament will show live coverage of as many election events (campaign stops, hustings and speeches) as they can possibly fit in (all without commentary)