It is absolutely possible, download an app called Handcent Messaging. Creates the iPhone style text messaging and you can set a picture to yourself so it looks like two people actually talking which looks kind of funny. Anyway go into Messages -> Settings -> Turn off Notifications for regular text messaging because you don't want the Handcent SMS notification and the default text SMS notification.
And you can go to settings in the Handcent application and set the Enter key on the physical keyboard to send.... ah reminds me of my Bold!!