This question is quite confusing, but I'll try to answer what I understand of it.
The iPhone 3GS, running iPhone OS 3.0, has voice dialing functionality, which can be accessed by holding down the home button or holding down the center button on the apple headphones. Apple has not opened up any APIs to access voice dialing (or any of the other voice controlling features) to third party developers.
However, if you want to create your own voice recognition algorithms this can be done. Google has created an app that lets you speak your desired search query into the phone and then it will translate the query into the appropriate text and perform the search.
Apple does allow calling a specified number from a third party app. Use teL:
followed by the appropriate number.
So if you want to implement voice dialing, you have to roll your own voice recognition/detection software, and then use the teL:
URL to place the call.