I have a Linksys WRT54G router and a W311 Netgear Wireless NIC. My PC is running Windows XP Service Pack 1.

In the bottom right hand corner the wireless card appears as being connected. It tells me the signal strength is excellent and the mbps. But I my internet connection will not work. I have tried pinging the router and I get "request timed out". Are these two devices compatiable? Is there anything else I can try to get them to communicate?

Thanks.

first, make sure that you have a valid IP, an invalid IP would be 169.254.x.x. secondly, right click on the connection icon and "view available wireless networks" make sure you are connecting to your router. XP will sometimes automatically make a connection to the first unsecured wireless network it finds, make sure you are connecting to the right SSID. Next, do you have WEP enabled, if so, do you have the key set up on your computer.

I am using a valid IP address and when I click on view available wireless networks only one appears. I am connecting to the router. I don't have WEP enabled at the moment. How do I check that I am connecting to the right SSID? I think I am, but I'll check it out just to make sure. Also I hovered the mouse over the connection and it appears to be connected, but I'm unable to ping the router or view any web pages. Could it be that the netgear wireless NIC and the Linksys router are incompatiable.?

To check the SSID, you can hardwire to the router and pull up the interface in a web-browser(just enter the default gateway into the browser) then look to see if it is the right SSID(which it prolly is since there is only one showing up.
Try connecting wirelessly again and pull up the interface, if you can pull up the interface wirelessly then your hardware is working fine.
Also check for any network bridges and delete any you find(many times network setup wizard will create these for no reason) Also, are you using a setup utility for either the router or the card? If so, uninstall them, uninstall the card and allow it to reinstall its driver. In XP, the Wireless Zero Config doesn't play well with third party config utilities. Router setup utilities are worthless because most of them won't properly detect your dsl/cable, so you may need to use the browser interface to set all that up. If all else fails, unplug your modem's power for at least five minutes, then set it all back up again.

As for your compatibility question, yes they should work together fine. If you have any doubts, download the latest driver for the card and update the firmware for the router.