Some notes on Virtual Dealer Plugin - used in MT4
http://www.stevehopwoodforex.com/phpBB3/viewtopic.php?f=28&t=364  << this guy's forum is full of MT4 goodies!
http://www.forexfactory.com/showthread.php?t=70582
http://www.forexfactory.com/showthread.php?p=4894499#post4894499
http://latimesblogs.latimes.com/money_co/2011/08/largest-foreign-currency-broker-hit-with-largest-ever-fine.html
http://www.forexfactory.com/showthread.php?t=263131
http://www.forexpeacearmy.com/forex-forum/general-forex-talk/9019-virtual-dealer-plugin.html#post65277
http://thefxview.com/2013/07/23/virtual-dealer-plugin/
http://www.forexrazor.com/en-us/school/tabid/426/ID/437468/finding-a-reliably-fast-and-honest-broker#virtualdealerplugin

This should be the docs for VDP: http://www.4shared.com/office/D6fq_qlw/metatrader_virtual_dealer_plug.html?locale=en

This appears to be a detection tool for VDP: http://4xtrader.net/4xsentinel/