The Netgear MA401 will work on the 2.6 kernel that Fedora Core 2 runs on, but I've not tried Fedora myself (but don't loose heart!). However, I did have to flash the firmware of my card first to get it running. There's an excellent HOWTO here http://linux.junsun.net/intersil-prism/
. Without the updated firmware, it does seem to work at all.
Do you know if you are running any kind of wireless encryption on your access point or router? If so, try going back through what steps you have already done (I'm guessing you've been going through a HOWTO), but with encryption turned off on your access point / router and see if you can connect.
Also, try typing in "tail -f /var/log/messages" into a console window, then unplugging your Netgear card, then plugging it back in. The console should start spitting back a load of messages about what it is doing. Copy and paste this into your post so we can check if it's loading the correct modules. I don't know if FC2 will have the modules built-in to the stock kernel.