My partner in podcasting, Stuart Sharpe has created a great application for iPhones for the general election. It's called Election 2010 (website is here).
As Stu says it:
...gives you tons of information about the general election. All through May 6th and 7th, this app will provide live results, telling you which seats have changed hands and which party is out in the lead. Also in the app is information about all 650 UK parliamentary constituencies (with quick links to more details from Wikipedia and UK Polling Report). You can view seats in your local area, see a map of every seat, and keep seats bookmarked for quick reference during the election. There’s also details and information about over 4,000 election candidates, right at your fingertips.You can even send candidates emails, or call them on the phone, right from within the app.
I know how much work he put into it and it is very impressive. I expect it will really come into its own on election night once the data starts pouring in.
You should really try it for yourself.