Using pg_restore -j number-of-jobs can

".. dramatically reduce the time to restore a large database to a server running on a multi-processor machine."
http://www.postgresql.org/docs/9.1/interactive/app-pgrestore.html

Our small-to-medium size database (4GB as a script dump), had been taking 90 minutes to restore.  Switching from "script format" to "archive format" (pg_dump -Fc) and restoring with -j 2 now takes 45 minutes.

References:

1. http://dba.stackexchange.com/questions/8855/does-my-choice-of-pg-dump-format-impact-restore-speed
2. http://www.postgresql.org/docs/9.1/interactive/app-pgrestore.html