Hi Roger,
I do not think that we can have a generic solution here. It will depend on the PC environment. In my opinion, the possible steps to achieve this will be --
1. Mobile invokes
Servlet on the PC
2. Servlet invokes necessary Windows DLL (assuming that your PC environment is WIndows) which calls your keyboard or mouse
I have never tried this before and this is just my thoughts.
It would be good to hear from someone who might have attempted something similar.
Arnab