The best WiFi USB adapter for Macintosh is Alfa AWUS036NHR
The best site to find drivers for Macintosh for wireless /WiFi USB adapters and cards is madwifi.org.
We do our best to support Mac users by posting relevant information to our Wiki Macintosh category: Whenever we gain some new information regarding Mac compatibility with a certain USB adapter or chipset, we post that information in our Wiki Mac support section
Much of the information on these pages is relevant to Mac users:
Set-up & troubleshooting of wireless USB adapters & cards
Mac OS 10.6.7 compatibility with Alfa WiFi adapters: AWUS036H and AWUS036EW are not compatible with Mac OS 10.6.7 (the same applies to any WiFi USB adapter with RealTek RT8187L chipset). COMPATIBLE Alfa WiFi adapters: We have verified that AWUS036NH, AWUS051NH, and AWUS036NEH are compatible with Mac OS 10.6.7.
The reasons that we make no guarantee of Mac compatibility with most of the wireless USB adapters that we offer, is because:
There are many Mac OS’s and versions of those OS’s, and compatibility with certain drivers often varies by version number: We cannot make blanket assurances of compatibility with certain Mac OS’s.
Therefore, in the past we have found many difficulties in trying to sort out the compatibility nuances among the various Mac OS’s, versions, and the drivers and chipsets.
Our staff all have Windows backgrounds and so we do not have sufficient Mac technical experience to make certain distinctions regarding compatibility matters.
Many wireless cards & USB adapters come with mini-CD which does not work in Macintosh
In conclusion: We found that we have to leave it to the Mac-using customer (who probably knows more about Mac technical nuances than we do) to do their own research. There is a lot of Mac compatibility information on madwifi.org.
Our Macintosh category of wireless USB clients and cards includes a few that are Macintosh compatible: Please read the compatibility notes on the page of the adapter/card before purchasing.