There are a lot of fun applications for the Apple iPhone and some of them are designed as perfect tip calculators. Maybe you’re not into digital calculations. If that’s the case and you want to kick it a little more traditional-like, then you should definitely check out this abacus app for the iPhone and iPod touch.
Each bead on the virtual abacus can be moved around just like on a real abacus and, I can’t say for certain, but I think that this application is multi-touch as well. After all, what good is an abacus if you can’t go all crazy like those herbalists in Chinatown. I just hope that the user interface and processor are fast enough to keep up with those flying fingers.
A video of the tool is also available, if you feel so inclined.