I first wrote about the desirability of "femto-awareness" in handsets almost a year ago. Since then, there have been various applications on devices (such as ip.access and others' demos) which have harnessed femtozone capabilities.
The announcement yesterday by Ubiquisys and handset integrator Intrinsyc is an interesting one. It changes the "theme" on Android phones when in femto range, based on what the partners call presence.
The exact mechanism for the trigger is a little unclear from the press release - in particular whether the femto is somehow "pushing" notification to the phone app, or if the connection manager is somehow detecting a changing cell ID or similar.
Either way, it fits in well with the general thesis that optimising handsets for use with femtos confers a range of benefits on both vendors and operators.