Apps: Smartphone walkie-talkie
There is a new program for your Android or iPhone. It's called Voxer, and it's free. It turns your phone into a walkie talkie /Nextel type communications device.
Great alternative to texting, or making a phone call. Especially while driving.
Just go to the Marketplace or the App Store, download and install. Register it, and you're good to go. It'll find people in your contact list who are also on Voxer.
The Android interface Is a bit better than the iPhone.
On your iPhone, go to the phone's settings, and set a notification for the program. Without that, you won't hear incoming calls.
On your Android, pick a loud, different ringtone.