MP - Good point, but the OP was talking about remoting *into* a Mac from a Windows machine, not vice-versa. ^_^
If the company allows it, you could always use a web-based service like LogMeIn. I've used it to remote into both Win and Mac from Windows, it works just fine, and the basic version is free (basic = no sound (I think), no Flash, no direct file transfers between the two systems (that's why I have an FTP server dammit), just straight-up "take over the Desktop/comp", but it functions as if you were sitting there at their comp otherwise). The only thing you don't get to see (unless they've fixed it recently) are the UAC popups in Vista/7 -- If those show up, you just get a static (unchanging, not "snow") screen until the user clicks it away.
“Always remember: you’re braver than you believe, stronger than you seem, and smarter than you think” - Christopher Robin