IMac won't connect to Sky Broadband

Hi,

I'd appreciate any help with an iMac/Airport/Sky broadband problem.
My set up is: iMac 20-inch Intel Core Two Duo running OSX 10.4. Sky broadband (Netgear) wireless router.

My problem: I can connect to the Net using an ethernet cable but that rather defeats the object of wireless.
When the router is switched on my Airport usually detects. I sometime has to switch the Airport off then back on before it shows up.
When I try to use the network the iMac asks for a password. I enter the password supplied by Sky and get an error message saying the Airport card could not log on. And so on... and so on...

The router is detected by my Centrino laptop and it is currently sitting next to the Mac so signal strength isn't an issue. The Airport can detect my neighbour's network so it seems to be working as well.

Any help would be most appreciated.

Thanks in advance,

Nige.