One of the things that I think is really great about the App store is that you can create applications for very specific niches. Pitch Pipe is one such application. (for full disclosure’s sake, Pitch Pipe was conceived by occasional Apple Gazette contributor Drew Corbitt).
Pitch Pipe for iPhone/iPod Touch works just like a traditional pitch pipe that you can get at any music store. The benefit of having it as an iPhone application is that you always have it in your pocket, and you don’t have to carry around any additional pocket objects.
The App is simple, and does exactly what you would expect it to do. You simply touch the note that you want played, and it plays for you, allowing you to tune by ear. It’s $2.99 and available right here.