Apologies to ressurect a year old thread but i thought this might help.
I have been trying to setup my Netgear WNA3100 usb wifi dongle for about week and the connection has been really touch and go. Got it working but it takes long to connect to a WPA2 encrypted network at home.
After a suggestion on a local forum (South Africa) I bought a Toto-Link N150UA dongle and this one was literally plug and play. Found my network and connected immediately after entering the password.
This is the lsusb of my device to show you the chipset:
Bus 002 Device 005: ID 148f:3070 Ralink Technology, Corp. RT2870/RT3070 Wireless Adapter
Dont even try NetGear, go for a dongle of this chipset or just get teh Toto-Link N150UA