Wifi usb 802.11n/g/b
in the latest version of pfSense work this usb wifi?
pfSense 2.1 is based on FreeBSD 8.3 which does not offer support for these Realtek chips.
Newer development versions might work, if based on FreeBSD 10 (not sure about current development status), with new rsu driver that was added to FreeBSD 10.
In any case, it will not work as an access point, which seems to be unsupported by the driver in FreeBSD.
Only driver with hostap mode support for USB-based NICs that I'm aware of (from OpenBSD) is ural for Ralink-chipset devices (most probably only some, not all!).
and find this model but be usb compatible?