I'm running Xubuntu 12.04 (and using whatever the default 'net connection software is). I was able to connect to wireless, no problem, out-of-the-box. I've successfully connected to my own home network (WPA secured) as well as the unsecured network at my local Starbucks. However, I can't connect to the unsecured wifi network at the library. The network connection indicator is stuck in "connecting..." mode.
I'm currently connected to the aforementioned network via WinXP, so I'm sure it isn't a problem with the network itself.