I'm new to linux, and running Ubuntu 8.04. I can can connect to any of the other unsecured wireless networks in my apartment building, but when I try to connect to my own that is password protected I can not connect to the internet. From my wlan0 Properties, I select my network name, set password type to WPA2 Personal and enter the correct password, click OK, it changes the configuration without any problems or errors but still doesn't connect.
Please help, thank you!

Is "wpasupplicant" installed?

I just ignore the wireless GUIs (tried one almost 2 years ago and junked it in less than 5 minutes).
I just edit my /etc/network/interfaces file directly and have something like:

auto eth2 (that's my wlan)
iface eth2 inet dhcp
wpa-mode ap
wpa-essid "myessid" (case matters)
wpa-key-mgmt WPA-PSK
wpa-psk MYREALLYLONGENCODEDPASSPHRASE

To get the passphrase:

wpa_passphrase "my essid" "my passphrase - whatever it is"

After configuring that, "ifup eth2" brings up the interface. The "auto" part means the interface will also be brought up on reboot.