does vacuum still lock the table?

I'm reading through the "PostgreSQL 7.2 Reference Manual" to get
information on vacuum.

(Nice set of .pdf files at
http://www.ca.postgresql.org/ftpsite/doc/current/.)

What it says for FULL vacuum is:  "...and exclusively locks the
table."

I thought I remembered reading somewhere lately that the new vacuum
process no longer needs an exclusive lock on the tables for full
vacuum.  Is this the case, or was I dreaming?  Can anyone point me to
the correct document or usenet posting if this has indeed changed
recently?

Thanks,

Stéphane Charette