A wave file has sound encoded in it and not the string. If you and I say "Hello there" and save them as 2 separate wave files, the files will be different. So you will anyway have to play it back before converting it to text. Also, this kind of conversion will need a very advanced speech engine very similar to http://www.nuance.com/naturallyspeaking. Again 100% accuracy cannot be achieved.
«_Superman_» I love work. It gives me something to do between weekends.
Microsoft MVP (Visual C++)