Wireless security

I have a wireless internet device ( linksys wusb11 ver. 2.6 ) that I want to use with my WRT54G. Without changing firmware, or anything like that how can i secure my connection, such as encrypting the data i send using ie or firefox. Soon, i will most likely have a chance to put in my 54g pci card (linksys).

Also, if anybody knows about these devices and linux, could you tell me if they are compatible with either ubuntu 6.10 or 7.04?

Go to wireless settings (or encryption or something similar) on the wireless router, and set the security type to WPA-PSK (or personal or similar), and pick a key you will remember.

Then go to the settings of any wireless cards/adapters that connect the the network, and use the same security settings on them. Then your wireless LAN will be encrpyted, and nobody can access it without the proper key.

Will the data that goes through the air be encrypted too? Sorry, i'm kinda a noob at wifi, because i'm a firm believer in wired connections, but i'm moving my comp into a room that doesn't have a ethernet connection.

Yep, it encrypts every packet that gets sent over the wireless connection.