This KEXT enables most Broadcom 4300 series wireless adapters to work as Airport. I have used this on a couple different setups.
Installation involves several easy steps.
1. download Kext Helper
2. back up original IO80211Family.kext
3. drag the new IO80211Family.kext onto Kext Helper. It will ask you for your password.
This will install to /System/Library/Extensions
If you wish, you can also add the file to /Extra/Extensions
The following Chipsets should be supported
BCM 4311 (Natively Supported)
BCM 4323x Family
The following card models should be supported
Linksys PCMCIA Card WPC54G
Netgear WN311B (v1 & 2)
Probably tons of other cards, as long as they have a supported chipset...
I take no special credit for this KEXT. Even though I have written this KEXT and made this available to the community, this hack can be done by anyone with a text editor and a little know how. My goal here is to make a KEXT available to the community that can be installed and will work on as many Broadcom chipsets as possible, and to do it in a Vanilla friendly way.