VECTOR: Looking for net tool for finding old states of webpages

There is at least one free tool out there that lets you find old states of  
webpages.  just tell it the web site address and date and it will usually  
display the page as it was.  Problem is that I can't find it now that I  need it.
 
What I am after is the document from Arcadeshop site that describes modding  
the WG6100 replacement HVU to run with Amplifone.
 
 
Thanks
 
+++++Ask me  about Retrocade 30-in-1 MultiPac kits for Midway Pac Man and Ms 
Pac Man boards  and same kit already attached to a new JAMMA PCB. Also we now 
have purchased the  rights to WG6100 (Tempest, etc) new deflection boards and 
HVU boards. Also HVU  boards for Amplifone (Star Wars). These are version 2 
with no extra wiring or  mods necessary. Ask about Star Wars overlays and new 
cabinets for Midway  cocktail, upright, mini, Dragon's Lair, Williams, Golden 
Tee Fore, and  Ultra-MAME++++