TVPredictions says yes. Although the network is already available to some Comcast, Time Warner and Charter subscribers, most cable customers don't have the channel yet. According to their source the channel will be added in Philadelphia at the beginning of August, and roll out in other cities shortly afterwards. With the Xbox 360 already available and the PS3 debuting this fall, their 18 to 34 year-old target demographic has an increasing number of reasons to pick up an HDTV and MTV is obviously looking to be at the forefront. MHD getting more exposure on a national level will almost certainly bring more viewers (and subsequently more HD content) than other cable networks making the switch like HGTV and Food Network.
A big question is whether this will be in addition to ESPN2-HD or replacing it, with the sports network fading out in many areas post-World Cup the way Universal HD did after the Winter Olympics. While Real World HD would be cool, we need Cribs in high-def so we can look at other people's HDTVs on our HDTVs.