Read Slash Dot occasionally and notice that WEP is insecure. http://lmgtfy.com/?q=WEP+insecure+site%3Aslashdot.org
Move away from WEP (its been known for 5 years to be easily hacked).
WPA2 is where you want to be. I had a laptop with a mini-pci network adapter built in that was old enough that it didn't support anything but WEP. 8 bucks got me a replacement card from Amazon, which did WPA2.
Computers are easy to upgrade. Some stuff is harder.
Some stuff is a lot harder. There are many legacy network devices that only support WEP (Wii, DS, Roku, not sure about XBOX, many wireless printers etc). Most do not offer firmware upgrades, so what is the average end user supposed to do? Stop using the stuff or go out and spend thousands on replacement gear. The worst part is much of this was released well after it was known that WEP was broken but they kept releasing products that just use WEP.
We are experiencing system trouble -- do not adjust your terminal.