The most known and successful application that enables user to send/receive SMS/MMS called SwirlyMessages by SwirlySpace AB is also supported on iPad that support 3G. This app works perfectly on jailbroken devices as well as non-jailbroken apple devices. The good news is that the applications works perfectly on iPad 2 as well.
There are different models of iPad based on their space, color and connectivity. iPad that support Wifi+3G are unable to send/receive messages. But with the installation on iPad devices you can send or receive messages easily. It was expected that may be due to the new hardware, there will be compatibility issue with iPad2, but it works perfectly on iPad2.
It is the best application to send and receive SMS and MMS with iPad. With SwirlyMessage you can easily backup your messages by syncing it with iTunes, with every message you can attach a signature at the bottom as well as GPS Location. It also supports the feature tha you can send message to multiple people at a time. Using this application you can send free sms to those recipients who have installed SwirlyMessgae. Here is a list of all the packages provided my SwirlyMessage.
