^I second that. The Intel heatsinks are EXTREMELY annoying to install, but taking them out is pretty easy, I think. All you have to do is what Aastii said: twist the little push-in things counter-clockwise. You should hear a little clicking noise for each one, if I'm remembering right. Then it should come right out after lifting it up. It sounds like you have a different kind of heatsink, though. If it's an Intel stock one, it should look like this:
EDIT: After looking at that one pic by Cravin, it looks like you do in fact have to squeeze those little tab things on whatever heatsink that is. It's not stock Intel, but it looks pretty similar.