Looking for cheap alternatives to SMS for the iPhone? There's an app for that.

Imagine that you're at home one night and want to send a message to your partner or roommate or someone else, but you really don't want to get out of your chair, and you don't want to yell loudly enough for them to hear you. So pick up your iPhone, but you don't want to send an SMS or call them. Surely there's an app for that...

Actually, there are several; some better than others. Take Texter for example. For 99¢ you can send messages back and forth with other people on the same Wi-Fi network. Sounds promising, right? After all, SMS costs are ridiculously expensive, so why not pay a $1 fee to buy an app to send messages back and forth.

The idea isn't bad, but the implementation is. First of all, Texter only works over Wi-Fi. And not just any Wi-Fi. Both users must be on the same Wi-Fi network. But maybe everyone in your family has an iPhone or iPod touch, so you're still willing to give it a try. Well, don't open your wallet just yet, because there's one more detail that we need to mention -- Texter doesn't support push notifications. Since Apple doesn't allow third party apps to run in the background, the end result is that you can only communicate with other Texter users if they already have the application open on their iPhones.

I can't even imagine a "use case" for this application. Who would sit around with their iPhone on, running an application in the hopes that maybe someone in the same home/office with the same application might want to chat with them? It simply is never going to happen.

If you want to avoid SMS charges, but still want to send quick messages to other iPhone users, why not use AOL's free (ad-supported) AIM iPhone app? It works over EDGE, 3G, or Wi-Fi, supports push notifications, and also allows you to connect with a slew of other people besides iPhone users.

Maybe you don't like AIM or SMS. Maybe you really like the idea of having an iPhone app that is quick and easy and doesn't require any login or giving away your cell phone number (like SMS does). If that's the case, checkout the 99¢ Ping! app for iPhone. It also works over EDGE, 3G, and Wi-Fi and supports push notifications. You'll also have that healthy self-satisfaction of knowing that you are only communicating with other red blooded iPhone/iPod touch users.

I'm sure there are a slew of other alternatives to SMS for the iPhone that work over EDGE/3G or Wi-Fi and support push notifications. Tell me about your favorites in the comments (bonus points for including an App Store link).