I recently got a AWUS050NH and out-of-the-box it only was able to monitor on channel 1 (common problem I hear). I was able to get it working properly following a tutorial here hxxp://forum.aircrack-ng.org/index.php?topic=5755.0. Although, I am finding that having compat-wireless installed causes the b43 module to fail to properly load. I have tested and if I uninstall using "make uninstall", b43 works fine after.
When attempted to "modprobe b43"....
"dmesg | grep b43" returns this..........FATAL: Error inserting b43 (/lib/modules/18.104.22.168/updates/drivers/net/wireless/b43/b43.ko): Unknown symbol in module, or unknown parameter (see dmesg)
b43-pci-bridge 0000:06:02.0: PCI INT A -> GSI 22 (level, low) -> IRQ 22
b43: Unknown symbol ssb_bus_pcmciabus_register