Probably the wireless NIC chipset is not supported by FreeBSD 6.2.
Check:
http://m0n0.ch/wall/hardware.phphttp://www.freebsd.org/releases/6.2R/hardware-i386.html#WLANYou'll probably need Atheros but not AR5005VL based NIC.
If You can't find supported wireless NIC use ethernet NIC and a wireless access point.