The UK will be following Japan, South Africa and Australia who have begun to relax the rules regarding gay men giving blood. In a recent survey at Brighton Gay Pride it was estimated 95% of gay men were willing to give blood.
You can find out where and when you can donate blood in England and North Wales here, http://www.blood.co.uk/ , Wales here http://www.welsh-blood.org.uk/giving-blood/and in Scotland here http://www.scotblood.co.uk/