Current API documentation is available at Franz: http://franz.com/support/documentation/current/doc/uri.htm
ASDF-install package (obsolete) http://files.b9.com/puri/puri-latest.tar.gz
Alternate download (from the debian repository): http://ftp.de.debian.org/debian/pool/main/c/cl-puri/cl-puri_1.5.5.orig.tar.gz
Git repo:
git://git.b9.com/puri.git
There is a fork that extends puri to support userinfo and specialized uri classes and re-implements the parser with cl-ppcre at https://github.com/lisp/com.b9.puri.ppcre