over in the "AT&T Announces Ruggedized Samsung Rugby 4" discussion:
Modern Carrier PTT Solutions
Great phone, but a word of advice - don't pay the extra $$$ for PTT. There are better, faster, cheaper, and more reliable alternatives out there. Nextel was the only proprietary cellular PTT that actually worked well. Everyone else, including Sprint, offer only dumbed-down versions. The drawback is that VOIP PTT is hackable, whereas iDEN was nearly impossible to crack.
Unless your a business or government employee, Voxer, Zello, or any number of other apps are just as good as Nextel was - and far better than carrier push-to wait.