Well, this is a fairly sensitive subject. First question anybody will ask (I know that) is - "Dude, why do you want to change your MAC & connect to an AP? " Answer is, there is a fine line between 'stealing neighbor's internet' & learning.... This MAC changing is really simple in linux & this thing should work and if it doesn't work, I like to know WHY?

Scenario is - EEEPC 701 with BT3, built in atheros AR5BXB63 - works great in 'normal' condition, even supports monitor mode & injection. However, if I change the MAC,
macchanger -m 00:11:22:33:44:55 ath0
it can see the AP, but can't connect. Currently, AP is set to WPA but I've also tried to connect after changing it to WEP - no luck!! I'm using the "Wireless Assistant" to connect.

With the same system + USB Edimax, everything works just fine... I think this is an old problem, unsolved here & here and this solution didn't work for me. Any idea will be appreciated.

PS: I don't use MAC filtering.... if you are curious...