With the plastic cover popped off there is really no more that needs to be done to enable an overclocking device to be used with the Athlon. Most heatsinks just need to be attached to the aluminum heatspreader, but some systems may require it be removed as well - for instance the MCW2000 has a copper plate which attaches to the CPU core, and L2 Cache directly in one configuration. To remove the aluminum heatspreader there are a few more steps. More caution is required here as one slip of a tool and the PCB could be scratched into oblivion.

Removing the aluminum heatspreader and clips:

 

The easiest way I found to do this is with a small awl, screwdriver, or pair of needle nose pliers. The trick is to slightly bend out the little fingers grabbing the metal pins, and holding the PCB to the aluminum plate. In this picture we can see that the bottom right clip has had one of its fingers bent back slightly, the other three need to look like that before attempting to remove the clips altogether.

Once all the outside fingers  have been bent out a bit, it is a simple matter to bend one of the inside fingers a bit, and the clips will generally come off easily then. If done right, the tools should never come in contact with the PCB, and both clips can be removed to leave the PCB like this... allowing the aluminum heatspreader to be removed.