Hi solaris,
yes it's possible. I'm using a EDIMAX EW-7811UN dongle and the NetworkManager daemon. To configure your WiFi connection, first login to the device using SSH (if you are on a windows machine, use a client such as Putty). See
here
for more informtion. Then make sure the network manager is installed. It may be installed already and if not, just run these two commands (assuming you are running a newer firmware image with Debian):
apt-get update
apt-get install network-manager
And finally configure your wifi network using e.g. the tool
In case your wifi device doesn't show up, the dongle's chipset might not be supported or you may have to install an addition driver. But I guess most dongles work out of the box.
Regards,
Matthias