Check Point offers a large suite of VPN products, and I believe they now have some policy enforcement solutions as well. StillSecure is a new software company that also offers products to enforce policy based on these sorts of criteria, and they look to have a huge amount of potential.

Personally, I think you are making a grave mistake, allowing computers that are NOT company owned assets to connect to the network via VPN tunnel. You can buy all the software you want to try and enforce policy, but there are ways to counter that (or try to). Plus, you have no idea what they have been doing with their home PC's; you could be opening the gateway to trojans, worms, malware, virii, p2p traffic, etc ad naseum.

A better option is often to use a secure application gateway to provide access to specific resources (Citrix is the main provider of the software to do this, but there are others, I'm sure.) VPN is not the best option, most of the time; however, it is difficult to get non-security management to realize the risk vs. benefit, and many organizations end up spending a lot of money to give VPN access to many people who really don't require it.