Can the built-in OS X "Location" feature auto select locations based on wireless networks? My home network is very secure, but my school's wireless network is open, which makes it vulnerable to wireless sniffing (e.g. with Firesheep). I just discovered the Location feature and I think it's really neat, but it doesn't make obvious a way to automatically switch Location based on which wireless network is currently connected.

Is this something which it is capable of, and if so then how do I set this up? Otherwise I guess I will use a program like NetworkLocation to do this; I'd just like to avoid paying for a program if possible.

(I'm using the latest Snow Leopard 10.6.5)
Since you mentioned Firesheep, let me put in a plug for Sheepsafe:

Sheepsafe was built to automate the task of switching your network configuration to use a SOCKS proxy whenever you join an untrusted network.
Sheepsafe works by keeping a configuration of known safe wireless networks. When you join an untrusted network, Sheepsafe switches to a network location that has a SOCKS proxy configured and starts a SOCKS proxy by SSH'ing into a remote server, thus protecting your browsing traffic from FireSheep and other snoopers on the local network. When you switch back to a safe network, Sheepsafe switches back to the default, trusted location and shuts down the SOCKS proxy.