While I haven't had much time to research the issues surrounding speech recognition in a driving environment, I have read through the apple documentation and it looks promising that you could do anything you want with it if you are a developer. However you are probably not, so iListen seems like the better solution for you. iListen supports apple script, although I don't see any where on the site that you can fill in the blanks in the apple script. ie "search 'BLANK'.
That is something you might want to ask the company before you spend the money. They also seem to have an iTunes ScriptPak,
http://www.macspeech.com/store/produ...roducts_id=188. That might be something to take a look at.
If I would contact the company and ask if their product supports that use before going out and purchasing the software.