>Can anybody show me how to :-
>
>1. find the ethernet card number (MAC) of workstation you are running?
>

Look at either the MS Winsock control, or dump the output of the command line IPCONFIG to a texrt file and parse it.

>2. given a IP number of a machine within a LAN, find the ethernet card number(MAC) of that machine?
>

The Win2 has API calls to do this; they aren't completely trivial to implement. You can buy the functionality in any of several ActiveX products, and it might be available as well from Rick Strahl's wwIPSTUFF.