People have been complaining (not without reason) that without any
documentation they can hardly test the new PITR code. I have hacked
up and committed some rough docs that should be enough for testing.
They're on-line now at
http://candle.pha.pa.us/main/writings/pgsql/sgml/backup-online.html
and should within a few hours be visible at
http://developer.postgresql.org/docs/postgres/backup-online.html
(but right now the latter page contains only an introductory blurb).
regards, tom lane