I would like to use my MacBook Pro (2010, with mini DisplayPort) as an external monitor for my Windows 7 PC. Before I buy an adapter, I want to know if it's even possible.
What I would suggest trying out is using a tool called Synergy. It doesn't share monitors, but it allows you to share one pair of keyboard and mice between multiple computers. Thus allowing you to have a similar set up to an external monitor. Here's a link to their website.