upgrading drivers of 2.4 kernel to 2.6 kernel

Dear Friends,

I am PCI cards of Advantech, and they are used in Data acquisition
systems.They are written for 2.4 kernel and i want to upgrade the to
2.6 kernel.
I want to ask what are the changes which i have to do in
Makefile,loading and removing modules and other important aspects so
as to work similar as it was working with 2.4 kernel.