iPhone and Android handset users need to download an app called Heytell immediately.  For those that remember the push to talk feature that Nextel touted back in the day, you'll understand the concept pretty quickly.  Press the button, speak your message, release the button, and your message is off to the recipient.  If the app is open then you'll hear the message immediately.  If the app is closed then you'll receive a notification that there's a Heytell message waiting for you.

So why use this app when you can just text?  Most of us have a limited text message plan, so this is a great way of not going over our limit.  It's much quicker, and there are just some things that don't get conveyed very well over text.  Sarcasm is the first thing that comes to mind, immediately followed by trash talk.

I've been using the iPhone version of the app for the past month or so, and I have run into very few issues.  The messages get sent/received very quickly.  You do have to delete conversations every now and then because you won't receive new messages if your inbox is full*.  The problem is that the app never indicates when your inbox is full.  Hopefully we'll see a fix for that in a future update.  Best of all, the app is completely free.  Here's the iTunes link.  Android users, you're on your own.

*edit* Check the comments for further clarification on the issue of not receiving new messages.