Venue and Lodging Options
CiviCon 2012 is being held in Central London at the Westminster Hub:
80 Haymarket, London, SW1Y 4TE
Training and Sprinting Too!
New to CiviCRM, or want to brush up on your skills? Consider arriving a few days early for the 2-day comprehensive User and Administrator skills course.
London abounds with things to do, places to go and sights to see, and critically for many Civi-folks - great food. Give yourself a few extra days if possible to enjoy and explore!
You could try https://www.airbnb.com or be adventurous and try the free(!) couchsurfing option - http://www.couchsurfing.org. There are loads of hostels around central London as well - use http://www.tripadvisor.com to find somewhere decent.