Guitar tuner API for O2 XDA II PDA using VB.NET Framework

I'm a budding musician and am just trying to develop a very, very simple guitar tuner to reside on my O2 XDA II. I just want a simple screen to be able to choose which string i wish to tune with my stylus on the PDA screen and then when i pluck that string on the guitar a green or red button on the screen will tell me whether it's too low or too high. The PDA will be placed next to the guitar and the mic on the PDA will pick up the sound. My question is whether there are any 'off-the-shelf' API's available that i can paste into VB.NET to analyze the guitar string frequency against the PDA crystal freq? Rather than creating a fourier analysis from scratch, i'm just wondering if anyone knows how to program a small executable to analyse frequency and compare this against set guitar string frequencies. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform Just need application to run on O2 XDA II PDA. The platform on this is Windows Mobile 2003 and i need the code to be written in VB.NET Framework.