Before considering using m0n0wall as an access point, read this FAQ entry.
These cards are broken into two lists - readily available cards, and discontinued / difficult to obtain cards.
Currently all g, b/g, and a/b/g wireless cards are incompatible with m0n0wall. These require drivers that are only found in FreeBSD 5.x and 6.x, while m0n0wall is on 4.11. They will be supported when m0n0wall is on a newer version of FreeBSD.
The following list, to the best of our knowledge, is 100% accurate. Please report any findings to the contrary to Chris Buechler.
Not all wireless cards support hostap mode! (i.e. can function as an access point) This is a limitation of the hardware itself, not m0n0wall or FreeBSD. If this list does not say "no hostap" next to the card, it should support hostap.
The m0n0wall Documentation Project does not endorse any vendors you may find through froogle.google.com. We simply link there for your convenience. The searches provided may also bring up unrelated hardware in addition to the compatible hardware.
Cisco Systems Aironet 340 - no hostap
Cisco Systems Aironet 350 - no hostap
D-Link DWL-520 - NOT DWL-520+ as it uses a different, unsupported, chipset.
D-Link DWL-650 - Revisions A1-J3 ONLY. K1, L1, M, and P revisions not supported.
Dell TrueMobile 1150 Series - no hostap
Some of the following do not support hostap. To determine if they do, search Google for the card name and FreeBSD, to determine which driver the card uses. If it is 'wi', it will work. Cards that use drivers other than wi do not support hostap.
Accton airDirect WN3301
Aironet 4500/4800 series (PCMCIA, PCI, and ISA adapters are all supported)
Airway 802.11 Adapter
Avaya Wireless PC Card
BayStack 650 and 660
Blue Concentric Circle CF Wireless LAN Model WL-379F
Cabletron RoamAbout 802.11 DS
Corega KK Wireless LAN PCC-11, PCCA-11, PCCB-11
ELSA AirLancer MC-11
Farallon Skyline 11Mbps Wireless
Farallon SkyLINE Wireless
IBM High Rate Wireless LAN PC Card
IO Data WN-B11/PCM
Laneed Wireless card
Lucent Technologies WaveLAN/IEEE 802.11 PCMCIA and ISA standard speed (2Mbps) and turbo speed (6Mbps) wireless network adapters and workalikes
Lucent WaveLAN/IEEE 802.11
Melco Airconnect WLI-PCM-S11, WLI-PCM-L11
NCR WaveLAN/IEEE 802.11
NEC Wireless Card CMZ-RT-WP
NEC Aterm WL11C (PC-WL/11C)
Netwave AirSurfer Plus and AirSurfer Pro
Proxim Harmony, RangeLAN-DS
Raytheon Raylink PC Card
Toshiba Wireless LAN Card
Webgear Aviator Pro
Xircom Wireless Ethernet adapter (rebadged Aironet)