I'm also using the Fedora 17 beta with Kernel 3.3 and have been experiencing the same issues. I'm using a USB Wireless Dongle from my old Samsung BlueRay player. It's a WIS09ABGN which is based on the linksys wireless chipset (though of course now I Google it I can't find it!).
Anyway, was all working rock steady until a few days ago when upgraded to 3.3 Kernel. Now intermittently it drops out, sometimes it comes straight back up but occasionally it just dies and I have to unplug it and plug it back in to bring it back up. Service Network Restart doesn't seem to do the job unfortunately.
---------- Post added at 08:55 PM ---------- Previous post was at 07:45 PM ----------
And just to elaborate. I'm on Kernel version 3.3.2-8.fc17.x86_6