Is there a way to find mapping between MAC address to IP address in C#. i think RARP should be able to do that, is there an API available in C# for that
In case you are looking for an API based approach and are not able to do a Process.Start() take a look at this:
http://www.codeproject.com/KB/IP/host_info_within_network.aspx
It allows mapping of hostname, IP address and MAC address.