I think that the AppMart is an old listing. It was originally spec'd by the original author to run under multiple OSes.
I'm pretty sure Borte will give more specific information. However, our long range intention is to have OM run on multiple platforms. It currently runs under Windows. ReadheadedRod is the only one experimenting with alternate platforms right now.
As to how to try it on ARM, I don't know. My best guess right now is with Linux and Wine (but that's just a guess).
Let's wait and see what Borte has to say.