Cliff Brake has announced that there are now packages of Mono available for OpenEmbedded which you can use on your OpenMoko NEO1973 phone, to install, he says:
add the following to a /etc/ipkg/*-feed.conf file: src/gz mono-armv4t http://dev.bec-systems.com/feed/openmoko/mono ipkg update ipkg install mono
OpenMoko is a completely open phone platform: starting at the hardware level (they have hardware kits for hardware developers) up to the software level (all the software is open source/free software).
Unlike other phones, this is completely open, and development and innovation on the phone are encouraged.
All those people that were disappointed that the iPhone is being locked down to developers, this is a good time to help improve a completely open platform. And you should be able to run Gtk/WebKit (the same engine from the iPhone) on the device.
A comparison chart for the hardware is here. OpenMoko today is a developer platform, so expect some updates in the near future.