Here are some links to get into PrintTalk — What is PrintTalk?
Here's a short explanation:

“PrintTalk is an open XML standard to communicate business information used in the Graphic Arts industry. It is maintained by the CIP4 consortium.”
(PrintTalk specification version 1.3 [PDF])

CIP4 Organization

• PrintTalk History
• PrintTalk Specification and Schema
• Torsten Ihrig: Foster City Interop 07 Tutorial PrintTalk [PowerPoint]
• CIP4: Customer to MIS ICS version 1.3 [PDF]
  

Cover Pages

Very old data, but better than nothing and also some cached pages from the old PrintTalk site that was hosted by NPES:

• PrintTalk Consortium
• PrintTalk Technical Briefing Paper
  
• PrintTalk FAQ
  

Other literature

• Parikshit Kulkarni: Exploiting JDF between customer and print-shop [PDF]
  

Software products supporting PrintTalk

The following list is not complete yet, drop a comment if you have additions:

• ixFrame (Framework)
• Optimus (MIS)
• Printplus (MIS)
• Admera VCS (MIS)
• connect it PrintTalk for Press-sense® iWay (Connector/Web2Print)