stored procedures / C-Language

hi,

i'm trying to find some documentation about writing stored procedures with
C-language.
i found description in postgresql's documentation but i don't understand
everything.

Aat present, i have a pl/perl stored procedure but it isn't fast enough, so
somebody recommend me to write it using c-language.
i don't know how to create this, and how asking the database, recovering
data and managing them.

For the moment, my application is running on Windows 2000 NT, is it possible
to write stored procedures using C-language ? may i write them using Visual
C++ or does i need to use ANSI compiler ?
does this code will run with Linux or Solaris ?

sorry for all these questions, but i don't how it works, and my application
must works at the end of the week :-(

thanks a lots

Will