some info as well in this post from hsx
We've begun work on a version of HSX optimized for mobile browsers, and we'd like you to be able to start playing around with it, while we are building it. Currently it's optimized for the iPhone, but expect compatibility with other mobile devices in the near future. It's admittedly rough around the edges, with many features disabled and zoom turned off... but you should have enough to now be able to place trades from the movie theater with your iPhone... and many additional features will be coming soon. Let us know what you think and what other features you'd like to see!