???You already can... from Apple's website for iPod Touch:
Want to hear some music? Just ask.
Ask and you shall hear.
Voice Control knows the music in your iPod touch. Want to hear something specific? All you have to do is ask. For instance, say Play artist Bob Dylan, and iPod touch does just that. Ask what song is playing and hear iPod touch answer. Tell it to play your favorite album, artist, or playlist. Speak simple commands such as shuffle, next song, and pause. Even have iPod touch play more songs like the one youre listening to.
LOL Maybe he meant a full on conversation? hahaha