My day job is with a company I co-founded, called SonoPlot, Inc., which manufactures and sells robotic systems for the printed electronics and biological research markets. Among other things, I write our control software in Cocoa.
I do Mac and iOS development on the side in my one-man company Sunset Lake Software, focusing on the iPhone and iPad. I provide the source code for my Molecules application under the BSD license, but I do sell an application called Pi Cubed as well.
I also taught a course on advanced iPhone development at the Madison Area Technical College, for which the fall and spring semesters' videos can be found on iTunes U. Class notes for this course (with links to sample code and other resources) can be downloaded here in VoodooPad format.
Like everyone else, I'm also on Twitter.