Do non-Thunderbolt monitors work with a DVI-D adapter on a Thunderbolt MacBook Pro? I have a MacBook Pro (15-inch, Early 2011). I want to hook two Dell monitors to it. They have VGA and DVI ports each.

I will be using the current DVI port on the MacBook Pro.

Will the Thunderbolt port work with a non-Thunderbolt monitor if I find a Thunderbolt to DVI-D adapter?
I have the same MBP.  It only has a single displayport/thunderbolt output, which can drive a single monitor.  The only way for it to drive multiple external displays is to use a daisy chained Thunderbolt display, or an adapter that drives multiple displays from a single input (Matrox makes one) or possibly a usb driven adapter.