If its the Sprint Hero....First, get a different messaging client like handcent. from the marketplace. its free and really nice. muc better than the htc one. Then turn off the stock messaging by opening your "all programs" and select messages. when it opens click "menu" and select settings. in the settings menu uncheck all the boxes that are not greyed out. this way it wil lnot conflict with handcent or whatever you choose. It makes
mms messaging much easier and its way more customizable! Not to mention that the htc messaging client causes the phone to remain basically on even when its "asleep" disabling the htc messaging client will increase your battery life alot.