I have bcome a fan of something, but now i dont want to be a fan of it anymore, so how do I delete it?

Go to 'my clubs' on your profile, find the club and click 'unsubscribe'.

if you accidentally fanned either a CLUB or a USER or an ITEM you can read how to un-fan here.
im guessing its an item you want to unfan so thats the last one in this article, number 26!
link