Very little in the way of detail on this one, but Reuters are reporting that ARM will be demonstrating an Android-based prototype cellphone at the Mobile World Congress on Monday, thanks to information from “a source close to the company”.  So far the microprocessor company has only confirmed it will feature existing, commercially-available ARM-powered handsets such as Samsung’s BlackJack II and LG’s KS20.

Android is expected to feature strongly at the MWC, after a little was heard of the open-source Linux mobile OS at CES 2008.  In the time since it was announced last year, it faces strong challenges from established rivals the LiMo Foundation as well as more mainstream rivals Symbian, Microsoft’s Windows Mobile and Palm’s own OS.