There was a post and a lot of talk about this a few days ago. The ultimate answer came to be: false. Most CRs said no, m2m is a different plan.
However, when I check my plan online, it does say I have this for free, and when I check my text usage, it shows a lot less texts sent/recieved than I actually have, leading me to believe I am getting m2m text. I wish there was a definitive answer to this somewhere.
Edit: On a side note, does anyone else's plan online display their data plan and IM plan about 20 times? 19 of them showing no activity, and only one correctly showing your usage? I hope they fix this soon.