Ivolunteer_ori is a project mainly written in JAVA and JAVASCRIPT, it's free.
Volunteer App
Developing on iVolunteer
We're using git for revision control, you need to ensure you have a client installed to develop on iVolunteer. See http://git-scm.com/download for a download.
On a mac, my experience has been that using MacPorts http://www.macports.org/ is the easiest way to get git (as well as a number of other useful apps).
iPhone App: You need the latest iPhone SDK: http://developer.apple.com/iphone/program/download.html
Website:
We're using SporutCore as a javascript framework for the front-end on the application.
Getting the code: Code is on github