A FREE portal has been made to the complete archive of Participatory Design Conference (PDC) proceedings. The portal gives you access to all papers published in all Participatory Design Conferences since the first conference held in 1990.
The archive gives you FREE full text search and pdf-access to PDC-proceedings:
1990 through 2002
2004 (volume 2) and 2006 (volume 2)
The archive gives you FREE text search to title, author, and abstracts and full text pdf-access (through ACM Digital Library) to PDC-proceedings:
2004 (Volume 1) and 2006 (volume 1)
2006 through 2012
Good luck with the reading.