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:
http://www.wrox.com/WileyCDA/WroxTitle/Building-iPhone-and-iPod-touch-Applications-for-the-NET-C-Developer-with-MonoTouch.productCd-0470590734.html
Just bought a copy myself and was pleasantly surprised. It's 42 pages and $6.99 and comes as a PDF download.