I've seen answers at the ARC246 Yahoo Group where Butel Software flat out says versions for PocketPCs/Palms are not planned, so I would guess Uniden shares that outlook.
As for whether or not it's possible to control a 246T from a PocketPC/Palm, I'd say it's a definite YES because Uniden has been so cool about publishing the control protocols. But someone has to code the software. The sheer fact that serial interfaces for PocketPCs/Palms is almost non-existent is pretty much a dead-end unfortunately.
But you just never know...
Paul