Dual Monitors on Dell Laptop

Although I haven't tried it, I'd say yes. Nvidia has good support for GNU/Linux I find Nvidia works out of the box with Trisquel. I have a VGA and DVI signal using Trisquel and an Nvidia card. I use Monitor Preferences, to control the display on my monitor. To find Monitor Preferences, click the Trisquel logo bottom left, then System -> Preferences -> Monitors. I also use the Resolution Switcher app to select my preferred resolution. You can install it through Add/Remove Applications.

You might need an HDMI splitter/converter. You've a choice of either HDMI or DVI, depending on your monitors connector. There's some available at Deal Extreme: http://s.dealextreme.com/search/hdmi+splitter

Before buying anything though, if they have HDMI, try connecting the other monitor(s) to your laptop one by one, to see if they work separately.

Hope this helps, good luck. :)