If you want to book accommodation on line here are some links I have found very useful:
This will take you straight to Wimbledon! Enter your dates and Laterooms will offer you information on local accommodation in hotels and guest houses with availabiliity, official star ratings and (very useful) ratings by real people who have actually stayed there! Discounted prices are highlighted (but don't expect too many of them during the championships).
A very user-friendly site with no cancellation fees and like Laterooms has a map based search facility.