Atheros released open-source linux drivers for their chips and the corresponding reference design.
I don't know which cards use the Atheros chipset, other than ours.
The atheros folks are also cooperating with the FreeBSD project, so they are making a good commitment to open source with their products. FWIW, my trusty old Netgear MA401 card could barely hold a connection in Minneapolis, but my shiny new D-Link DWL-AG650 did a much better job. This is from ath(4) on FreeBSD. Not intended to be a complete list, just a good starting point.
Card Chip Bus Standard D-Link DWL-AB650 AR5211 CardBus a/b D-Link DWL-AG520 AR5212 PCI a/b/g D-Link DWL-AG650 AR5212 CardBus a/b/g D-Link DWL-G520B AR5212 PCI b/g D-Link DWL-G650B AR5212 CardBus b/g I/O Data WN-AG/CB AR5212 CardBus a/b/g Linksys WMP55AG AR5212 PCI a/b/g Linksys WPC51AB AR5211 CardBus a/b Linksys WPC55AG AR5212 CardBus a/b/g NEC PA-WL/54AG AR5212 CardBus a/b/g Netgear WAG311 AR5212 PCI a/b/g Netgear WAB501 AR5211 CardBus a/b Netgear WAG511 AR5212 CardBus a/b/g Netgear WG311 AR5212 PCI b/g Netgear WG511T AR5212 PCI b/g Nortel 2201 AR5212 CardBus a/b Orinoco 8480 AR5212 CardBus a/b/g Proxim Skyline 4030 AR5210 CardBus a Proxim Skyline 4032 AR5210 PCI a
Hope this helps,
Doug