What you have in the ic502 is a single handset that can handle both iden and cdma hence the front letters of both "i" and "c".
This dual capability does not yet exist in a smart phone.
There are iden (slow data) smart phones known as the i1 and its replacement the Titanium but these are slow data (2G) only handsets which makes for an odd smartphone experience because the only way they can do cool smartphone things is if they are hooked up via wifi (like when you are in a building)
There are smartphones on CDMA but they do not have the PTT feature that you want.
I would keep the ic502 a little longer and allow for technology to catch up. In the mean time I would recommend the Virgin Mobile Optimus handset that you can buy for $99 when found on-sale and for $35 per month it will do everything you want a smartphone to do. That $35 includes unlimited data and text but only 300 talk minutes but that is okay because all of your talking will still be done on the ic502 which work pays for.