There is also cCalc which is free and very good. Has the most needed formulas and bin/hex/dec conversion and everything. You need to use the plain cCalc, not cCalc pro,
N95 doesn't have all the keys needed for Pro, which has some more formulas and sci functions.
http://home.pacific.net.sg/~welic/cCalc.html
Give the page a minute to load or two, it is very slow from Europe or US.
Download links are at the bottom of the page.
Dayene:
You need to work on that warez paranoia :)
There is a bazillion of good free apps for Symbian and good reason to ask for one.