If you are picking up wireless networks but are not connected to any one of them, click the Network Manager icon in the System Tray (on the top right, the icon that looks like several curved lines [like waves] curving around a dot) and a list of wireless networks will show up. Select your network and type in any security keys you may have for it, and then you're all set!
Can you tell me the model number of your Linksys USB adapter? That may help me to point you to the HCL
so you can see just how it works with Linux.