Vlingo Pro is free in the app world for a limited time. I think that is going to be your best option. It works, but takes some getting used to. I have the kind of voice that Vlingo doesn't like to recognize, so it thrashes what I want it to say. I have it on the phone, but don't use it often.
I went to BB AppWorld earlier this evening and looked over Vlingo. It has a lot of recent bad reviews (and I'm not one to judge an app on just the first three reviews, either); that's why I didn't mention it before. I may still give it a shot while it's free.