I have two access points, a D-Link Gamer Lounge and a Time Capsule both configured in 2.4 Ghz n/g compatible mode using the same SSID. My iPhone and iPad can roam between the two with no issues. They automatically choose the stronger signal as you approach the closer AP. This also used to work fine in Snow Leopard. However Lion refuses to let go of the weak connection. Transmit rate drops down to 5Mbps as I walk away from the connected AP and standing right next to the other AP but Lion refuses to connect unless I turn WIFI off and back on again. In which case it picks the closer one. Same results on a Macbook Pro and a Macbook Air so it is not hardware specific. Are you aware of any way change the threshold of when to look for a stronger signal?