I wouldn't trust stuff like that as they don't sound too safe. Anyway most laptops have a plug for that so you can just use your laptop monitor and then the new monitor.
want to go dual myself but i have no room nor cash for another 24"er. Very handy imo, i love watching something and surfing at the same time. Personally have a Dell 2407-HC here. Sweet monitor imo, USB hub and additional connectors come very handy !