I recently switched from WinXP to Debian on my IBM Thinkpad T23 laptop. I used madwifi to get my Atheros 5212 based wlan to work. I just followed the steps in UserDocs/FirstTimeHowTo - madwifi.org - Trac and it works... sort of...

The problem is that my wlan connection works like it should when I boot my laptop, but not after suspnding or hibernating. The strange thing is that when I (from the terminal) manually bring down my wlan adapter and bring it back up and then manually reconnect to the network, it sometimes works, but usually it cant get a new IP (using dhclient). If I try anything from the network admin tool, it doesnt work at all. I usually need to reboot my laptop just to get wlan working again. Also switching between wired and wireless connections doesn't work. Wireless to wired is ok, but the other way around gives the same issues as described above.
So rebooting solves the problem, but I usually just dont have time to reboot over and over again. I

Another strange thing, the network connection icon in gnome only shows the wired connection, but when I just installed Debian, it showed both wired and wireless connections, even tho wireless didn't work at all. Now that madwifi is installed, wireless works, but has disappeared from the network connection icon.