Here are some sites you may find helpful and some you may just find interesting!
www.entertainment-resources.com/Parties/
http://www.makemywedding.co.uk
Event Management UK - Event Management and other related links
UK Entertainment Directory & Live Music Band Hire http://www.LastMinuteMusicians.com
http://www.silverdogmusic.co.uk/backflash.htm - Party Band Hire