How does OMS (Open Mobile System) relate to Android? So I've just read about "OMS" and a bit of googling suggests it's a fork of Android prevalent in China:
http://www.engadget.com/2010/02/02/china-mobiles-ophone-platform-goes-2-0-supports-winmo-api-w/

But it's not quite clear if it is also open source, what the differences to a "standard" Android system are, how to distinguish it.

Has anyone ever seen it or better documentation? Does it have any desirable attributes?

(Again I'm mostly wondering, because if it is a fork, could it possilby be the variation required for Dual-SIM support, meaning normal Android wouldn't have that.)
Apparently it's better known as OPhone and started as a fork from the original Android project, before Google bought it.  It looks to be mostly developed and supported by China Mobile, although there are rumors they might shut down the project.  OPhone 3.0 is expected in Q1 2012.