Ok maybe not so high seas, I'm just starting.
I've made an app for practicing chinese calligraphy. It's avaiable on android market for all devices with android >= 2.1.
It's free and with no ads just to help poor people like me who struggle with mandarin at buses.
No heave books my friends, all you need now is your mobile.
So If by any chance you learn mandarin I encourage you to install my app and give me feedback what you think
Name of the app: Chinese Primer.
I'm just polishing this one and already have a lot of ideas for more. ^^
This year's gonna be fun.