hmm.. i'll try to guide you through it.
1) unlatch the black plastic lever by obviously pulling it in the opposite direction.
2) using a flathead screwdriver. look on the side opposite of the black lever. You should see a small section whre you can put your flathead . Push down into the section and guide the metal latch out of the retention module
3) on the side where you just unlatched, push it in towards the black plastic lever as far as you can (it won't be much)
4) carefully wiggle a bit slowly, you want to try and break the air tight bond between teh HSF and the CPU
5) as you're doing that tilt the HSF a bit towards the black plastic lever side as you try to remove the other metal latch from the retention module.
unfortunately, when doing step #4, removing the HSF with the CPU attached onto it (which means you ripped it out of the socket), does happen. It's unlikely you'll bend any pins with the stock HSF though.
Be really careful when removing more larger heatsinks, like the XP-90. I recently just f***ed up my CPU cuz I bent a whole wack of pins due to removing that beast.
aren't there instructions on how to remove the HSF in the Athlon 64 instructions that came in the box?