Airport Extreme & Intel 4965AGN wireless
I just bought an Airport Extreme today (9/25/07), set it up with my home network with a mixed signal environment (b/g/n). I have a 2nd-gen MBP with the Atheros 5008 802.11n wireless, my wife has an older dell inspiron 6000 with an Intel 802.11b/g wireless card, and I successfully got both our laptops running! (By the way I really like the "Airport Utility" on the Mac, very nice)
Then our roommate has a new (~2month old) Dell E1405 laptop with the Intel 4965AGN wireless (802.11 a/b/g/n), and it couldn't connect to the Airport Extreme b/g/n mixed signal. When I changed the wireless signal to 802.11n ONLY @ 2.4GHz, the E1405 worked but my wife's Inspiron 6000 obviously couldn't connect (My MBP could still connect). The whole point of this post is in case anyone comes across this problem of the 4965AGN not connecting, Intel has updated drivers as of May 2007 that fixed this problem on the E1405, and both Dell laptops were able to connect to the Airport Extreme base station for b/g/n.
Link to the Intel Wireless WiFi link 4965AGN
http://www.intel.com/network/connectivity/products/wireless/wireless_n/tools.htm
Core 2 Duo MacBook Pro 2.16GHz, Mac OS X (10.4.10), Airport Extreme 7.2.1