Have just read 'the no-cry sleep solution' by Elizabeth Pantley which I really recommend, and am just about to start using some of her suggestions.
When breast feeding your baby to sleep, feed until baby is sleepy, and then unlatch and press your finger under babies chin to keep it closed, so that your baby gets used to falling asleep without boob in his/her mouth.
I though it was rubbish - but it worked first go! (the book said you might have to try up to five times) My dd fell asleep... without boob in her mouth, and didn't even cry about it...
Sorry if this is common knowledge... but I've been feeding to sleep for the last 5 months, so this tiny step forward is amazing. And that is the only thing I've tried from the book so far... will keep you updated.