The compiler is based on the original Portable C Compiler by Stephen C. Johnson, written in the late 70's. Even though much of the compiler has been rewritten, some of the basics still remain.
PCC debuted in Unix Version 7 and replaced the DMR compiler (Dennis Ritchie's original C compiler) in both System V and the BSD 4.x releases.
Some history about pcc is in the A History of UNIX before Berkeley: UNIX Evolution: 1975-1984 and in the Evolution of C.
A copy of S. C. Johnson's and Donn Seeley's 1978 ``A Tour Through the Portable C Compiler'' is available in HTML, Postscript or PDF. (For current pcc internal documentation, see the internals wiki page.)
About 50% of the frontend code and 80% of the backend code has been rewritten. Most stuff is written by Anders Magnusson, with the exception of the data-flow analysis part and the SSA conversion code which is written by Peter A Jonsson, and the Mips port that were written as part of a project by undergraduate students at Luleaa University of Technology (LTU).
It was publicly announced to the NetBSD community on September 14, 2007. Shortly later it was imported to the OpenBSD, NetBSD, and pkgsrc source trees.
On January 27, 2008, the version was increased to 0.9.9 as pcc supported C99 language constructs.