Okay, if you are running a kernel that new, perhaps it is Debian Squeeze (testing).
I hadn't realized, but this Intel wireless card needs some proprietary firmware to be installed. This is included in a package called "firmware-iwlwifi". There are some instructions here
. It isn't included by default in the distro because it is non-free software, but Intel have provided it in binary form for packaging.
The basic steps are to add the appropriate repositories, apt-get the firmware-iwlwifi package, and reboot (or use 'modprobe iwlagn') so that the driver module gets loaded.
If you have a look at "dmesg | more", you will be able to see if and when the wifi driver gets loaded.
Sometimes (if you have used other wireless cards on the same installation), the wireless card will come up with a different device name. You can edit the file "/etc/udev/rules.d/70-persistent-net.rules" to force the name for a particular device to be "wlan0" (based on for example the mac address). But you should be able to see the device using 'iwconfig' before you worry about that.