speech to text

Question

Hi,
     Is there any way to create a program in vs2005 or vs2008 for converting speech to text .Ie , for eg, if i say "Hello" then it should be typed in a textbox as "hello".can i create a dictionary of my own for this purpose where i can add specific words which is needed for me so that i can avoid all those which is useless for me for making searching faster.
if so please get the source code for me

Thanks in advance