So if you have rooted your phone here is a little tip that you can use that allows you to send and received text messages on your Kindle.
You can get software called DESKSMS or I am sure there are other types. Forward the messages to GTalk, Gmail or it's web extension. Then installed GTalk on your Kindle or open up the web interface for DeskSMS and your good to go.
I have found that GTalk works the best for me and I really have enjoyed using it this way. The kindle gets much better batter life than my Evo and this allows me to plug my phone in when I get home and then not worry about where it is while I am reading during the evening or when I am in bed.
Just a helpful tip