You should only have to enter the wep key once. Go to system prefs, Network and select your airport connection, then under the airport tab, you can tell your computer to connected to a specific network (your wireless network you created), and enter the password (wep key). Thats it, now you won't be asked for the password.

The above prosedure is for 10.2.x, but all Mac OS's that support wireless networking are able to remember your password, usually the option apears when you are asked for the password, or it is in the airport admin program.

Tom N.