I have a very strange problem. A co-worker of mine wants to switch to Linux (Slackware 10.2) and has a USB D-Link DWL-G120 which I have installed with ndiswrapper. All the ndiswrapper stuff appears to be working I get a message in "dmesg" with the device's MAC address and I can see the MAC address on my router/firewall. I use the following commands to configure the port
iwconfig wlan0 essid ESSID
iwconfig wlan0 mode Managed
ifconfig wlan0 up
dhcpcd wlan0

I get back a valid IP address from DHCP but I can't ping anything outside of the local machine. Any ideas? I am lost.

Thanks for the help

Try to ping by IP address instead of name; perhaps it's just a DNS configuration issue.

I didn't explain myself clearly but I was pinging by ip address. In fact I can't even ping my router.

have you tried just plain iwconfig to see if your connected to the ESSID?
Also can you check router to see if it is connected (My router tells what computers have what Ips etc.)

I would also check and make sure you don't have any kind of encryption needed to connect to the router

iwconfig does state that I am connected by giving me an access point and changing the essid after "iwconfig wlan0 essid ESSID". My router also tells me that the MAC address has connected. DHCP works it is verified on the computer and the access point but I can't ping using IP address any of the other computers on my network. I feel so close to getting ndiswrapper working but I don't have any idea what is wrong. No encryption is needed on my network because I have another laptop with wireless that works perfect and I have given it no WAP/WEP keys. Why would DHCP work but a simple ping fails?