crunchSMS is a free messaging app that adds new more functionality than the default SMS function within BlackBerry devices.
The messaging experience offered by crunchSMS is very similar to the iPhone SMS interface. Conversations are conducted within chat-style bubbles, allowing you to see the complete history of a conversation very easily.
Other features of crunchSMS include contact pictures, signatures, text snippets, password locking, and a blacklisting tool for blocking messages from unwanted contacts. crunchSMS includes a large set of fun smileys too, to help brighten up your messages.
Another handy feature is the Quick Reply feature that lets you instantly reply to an SMS message through crunchSMS as soon as it comes through.
Unfortunately, crunchSMS only supports text messages at the moment, and there are no MMS features such as the ability to send photos or videos via the application.
If you're looking for a more powerful alternative to the standard BlackBerry messaging utility, then crunchSMS is worth a try.