MacBook 2.16GHz Intel Core Duo: use as dual screen monitor with iMac 3.06?

I have a MacBook 2.16Ghz Intel Core Duo and an iMac 3.06Ghz Intel Core Duo. Lightroom 3 is installed on both machines.

Is is possible for me to use the MacBook as a second monitor/dual screen setup when using Lightroom? If so, what would I need to connect the two computers?

Many thanks