Geek Project: Get WPA to Work in Ubuntu
This is a great tutorial to get WPA wireless security to work with your Ubuntu Linux system with a wireless card. WEP is lousy security… so you REALLY need to use WPA! But, “out of the box” WPA isn’t available for your wireless card… so how do you do it?
Enable WPA Wireless access point in Ubuntu
The tutorial has nice screenshots and details on setting up WPA. Go for it!