ie, if you get messages like this:

Sep 5 09:12:56 localhost kernel: ipw2200: Radio Frequency Kill Switch is On:
Sep 5 09:12:56 localhost kernel: Kill switch must be turned off for wireless networking to work.

turn on the radio before suspend. ipw2200 gets stuck trying to initialise the radio and will hang during suspend otherwise (driver version 1.0.6). On my laptop, I do this with echo on > /proc/driver/acerhk/wirelessled in the suspend script.