Take a look at the "Hardware Compatibility List"
http://www.freebsd.org/releases/6.2R/hardware-i386.htmlCards with an atheros based chipset are good.
Personally i wouldnt use this card after reading its datasheet:
RF Pwr (EIRP) in dBm
15 dBm @ 54Mbps (802.11g)
19 dBm @ 11Mbps (802.11b)
Recieve Sensitivity
-70 dBm @ 54Mbps (802.11g)
-85 dBm @ 11Mbps (802.11b)
Others like the WLM54G-30dBm have slightly better stats
http://www.compex.com.sg/home/Datasheet/WLM54G-30_rev1.0.pdfOUTPUT POWER
802.11g
6-24Mbps 30dBm
36Mbps 28dBm
48Mbps 27dBm
54Mbps 25dBm
802.11b
1-11Mbps 30dBm
802.11b -92 dBm @ 1Mbps, -87 dBm @ 11Mbps
802.11g -90 dBm @ 6Mbps, -70 dBm @ 54Mbps