OK there’s been a lot of noise on the monotouch mailing lists relating to a change in the developer agreement with iPhone OS4 (Currently beta), specifically this clause…

“Applications must be originally written in Objective-C, C, C++, or JavaScript as executed by the iPhone OS WebKit engine”

Check the monotouch site for further information http://www.mono-project.com/newstouch/archive/2010/Apr-19.html

Dom