Sick of the plain-looking calculator that comes with Windows Mobile 2003? If so, the attractive AquaCalc 1.0 might be for you. It does not have add any functionality but it does look better. Currently in beta, it is available for free.
Note that you will need to have Windows Mobile 2002/2003. Earlier versions will require that you download the Microsoft .NET Compact Framework 1.0.
Source: PocketPC Paradise