The title says it all. An old buddy of mine Wally McClure has just released a short new eBook on Wrox that covers how to get started building iPhone and iPod Touch applications using MonoTouch. That should be of interest to the C#/.NET developers out there. You'll find it here:
Just bought a copy myself and was pleasantly surprised. It's 42 pages and $6.99 and comes as a PDF download.