BiteSMS

Here's an app I just downloaded the other day.  All I can say is, it's "awesomeness!"  Among the features I am loving so far:

- SMS privacy.  You'll have to input your passcode before opening your messages.
- Customized ringtones
- Signature in all outgoing messages
- Thumbnails of your contacts on each message
- And look at these smileys! :D

For more info, please visit BiteSMS.