One of my co-workers gave a short presentation regarding VPNs. Pretty softball stuff - the audience (us) was technical, and mostly knew what a VPN was, but institutionally we haven't spent a lot of time thinking about this sort of thing. Largely, that's because our campus network is mostly unfirewalled, and we've not had much need for it. However, the firewalls, they be coming, and about half of CS is currently firewalled.
The built-in OS X VPN works well enough with the solution we're currently using, but something that's been pulling at me has been Hamachi.
Hamachi has an OS X client, and Lifehacker has an article about Hamachi itself.
I don't know if this particular technology is really the solution for us - it appears to be aimed at our individual clients, since we're currently without a "corporate" VPN. I don't know if it's meant to really *be* that corporate VPN, but it's worth looking at anyway - several of our clients have their own private networks, and perhaps this would be useful to them.