I had such a touch time connecting my PSP to my wireless router that i thought i'd share the process for anyone else with the same hardware. The process should be similar for other Netgear wireless routers.
You first need to configure your router. You do this via a webpage, which is probably http://192.168.0.1/, depending on your setup. Default username and password are admin/password.
Select 'Wireless Settings' from the menu.
SSID, region and channel don't matter, but make sure mode is set to 'g and b' or 'b only'.
Select WEP security, Open system, and 64 bit.
128 bit is more secure, but 64 bit makes it easier to enter your wep key into your PSP.
In the 'key 1' box, enter a 10 digit hexidecimal string (contains 0-9, a-f). You'll need this when you configure your PSP.
Select 'LAN IP Setup' from the menu.
Make sure your router is enabled as a DHCP server (it is by default).
Go to the home screen of your PSP, scroll to the left ('settings') and the bottom ('network settings').
Select Infrastructure mode, then create a new connection. Give it a name then on to the next screen.
Select 'Scan' to find your network. It should figure out you want WEP on.
Type in your WEP key from before - this bit takes ages for the 128 bit key, but not too bad for the 64 bit.
Choose 'easy' address settings - this means use DHCP.
All done - save and test.
A guide by Cal Henderson of iamcal.com, April 2005