IV Calculator for a PDA

I downloaded the free Archimedes (SP). calculator from skyscape, but for some reason, it doesn't do what I need it to.

There isn't a "unit" that can be used for Heparin and Insulin, and if you are using calibrated tubing, it doesn't even ask the right questions.

Plus, it has a TON of calculators that I probably won't use...I need something where I can do IV calculations quickly without writing out a huge dimensional analysis problem so does anyone have any suggestions?