Simple audio overlay software

Hello, We are looking for somebody to develop a software that will enable to overaly voice on a song. The main features that we are looking at are: - overlay voice at specific intervals - overlay voice at predefined intervals - batch mode where you can overlay the voice on several songs at once. The voice to be overlaid would be in the form of mp3 or a microphone capture. We are looking for it to be a self install program. It would be nice if it could be cross platform (i.e: java) but it's not required. We will also considered people that can only develop the tool for the windows platform. Ultimately we would like to have a version that has ads and one that could be ads free for a very small fee, so it would be nice if the developer was experienced in ads network for software. This is a very high level overview and we will give more details to the winning bidder. Thanks,