Dig Dug Series

DIG DUG Deeper - http://www.us.infogrames.com/games/dig_dug_deeper/

KLOV: Dig Dug - http://www.klov.com/D/Dig_Dug.html
Background, cabinet style, game play and abstract information.

Microsoft Games - http://www.microsoft.com/games/arcade2/dig_dug.asp
Brief information on this arcade game.

Phosphor-Dot Fossils: Dig Dug - http://www.thelogbook.com/phosphor/digdug.html
A brief history of Dig Dug