@afteris: Low battery is one idea, do you know if you battery WAS low after you did the flash? But in that case it's obviously not low enough to load up the tux and start the loader. Maybe it has different demands for battery when flashing and booting. Are you able to charge?

ok, just an idea: Try to follow one of the guides to install a valid os on your sd memory (like nitdroid or meego) and see if the u-boot behaves differently than now. If it even boots into one of those, maybe you're able to access the meamo partition from there and do something that fixes this problem, like reflashing everything back to stock? Backing up your SD first of course.