Here are two conversion utilities for MySQL dumps.  Use the one you prefer.

The most recent version of my2pg.pl can be obtained from:

	http://www.omnistarinc.com/~fonin/downloads.php#my2pg

my2pg.diff has additional changes for CREATE FUNCTION.

Another tool, mysql2pgsql, can be found at:

	http://gborg.postgresql.org/project/mysql2psql/projdisplay.php