If you are looking for a way to control or access your PCs from your make, nows a good time to check out the now-out-of-beta Microsoft Remote Desktop Connection Client for Mac 2.
The beauty is you can access more than one PC through this.
More Secured and you can make mac key-shortcuts for it.
Yeah I am sure I will get a few responses about "why would I want to," if thats you don't bother. I just said it.
*Sidenote: My parents use TightVNC to do the same thing between two PCs and it does come in handy.
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Sources Cited:
Microsoft Remote Desktop Connection 2 now available - The Unofficial Apple Weblog (TUAW)
Connect Across Platforms with Remote Desktop Connection | Mactopia