Stratagus is ported to many platforms, so I was wondering wouldn't be great to play StarCraft, WarCraft 2 or other strategy games with touchscreen controls, like Red Alert for iPhone?
This engine is OpenSource, and you can download source from their site:
P.S.: It has been ported to Maemo, Symbian, Mac, Linux, AmigaOS 4, MorphOS and many others!