writing dll in python?

[nishalrs]

Hello All,

My main motivation is to build a collection of useful mathematical
models (that I have developed over the years) to design ultrasonic
sensors. This should be some sort of a library that should be able to
be used for desktop/web application development, to run in variety of
operating systems.

I am more than convinced after looking at python.org website, it is
the right tool for the job. I intend to learn python, but I am not
really sure, where to begin. 

Should I write all the functions as simple python scripts? Or is there
some facility for creating a .dll like library, that could be more
suitable for what in intend to develop?

Any help is much appreciated.

Regards,
Nishal