Looking for Inneroffice Access Tool, Workstation to Workstation [closed]
Solution 1:
Normally (like ChrisF already mentioned) I'd suggest remote desktop (RDP). But I get the impression in this case that you don't want to actually log in to this machine: someone might be using it, or there may be a monitoring tool running that you don't want to interrupt. I'm also unsure if there's a good rdp client for mac.
With those limitations in mind, you should consider a vnc program like ultravnc or tightvnc. Those should let you view the current desktop on the machine without interrupting anything and optionally let you interact with the desktop.
Solution 2:
To go from one Windows machine to another you could use Remote Desktop. This should be OK if both machines are behind the firewall.