I'm very impressed with this bit of software, which is easier to install and configure than I had expected. Selecting and releasing locos is very easy - probably easier than on my DT402D.
The JMRI web page for Engine Driver Throttle is here.
More information and the software can be obtained from here.
Note that Engine Driver throttle is for Android phones. For devices running iOS, you can use WiThrottle (which is not free) or WiThrottle Lite (which is).
What a great way to extend the life of an unwanted smart phone.
Thanks for looking.
NOVEMBER 2013 UPDATE
The latest version of Engine Driver allows three locos to be selected at once, and offers better consisting capability. I just tried out this latest version and had three trains running around the layout at once using my smart phone. It's kinda neat being able to run three trains from the one hand-held device.
I also tested out the improved consisting capability. You just keep 'acquiring' the locos on the same throttle, and when you're done the s/w allows you to specify which loco is "lead" loco (it defaults to the first selected), and to specify the direction of travel of each loco. You can add extra locos by 'acquiring' them as you want to. I didn't think to test how to remove a loco from the consist, or how to change settings such as the direction of travel of individual locos, once you've built the consist. Perhaps the worst negative was that when you release the top loco the consist is lost.
Anyway, this piece of software is certainly evolving in the right direction - and it's FREE!!