vhoster

Vhoster is akin to a graphical version of "rwhois" published by the author to give the facility to query for virtual domains hosted on the same IP address as your target network.  Vhoster uses the Live API to facilitate its queries.

It also allows for a reverse DNS lookup to determine if any potentially identified domains are in fact hosted on the same IP address as the target and reports any errors from the original findings.

It is available from here