Lanyrd's MySQL to PostgreSQL conversion script. Use with care.
This script was designed for our specific database and column requirements - notably, it doubles the lengths of VARCHARs due to a unicode size problem we had, places indexes on all foreign keys, and presumes you're using Django for column typing purposes.
First, dump your MySQL database in PostgreSQL-compatible format
mysqldump --compatible=postgresql --default-character-set=utf8 \
-r databasename.mysql -u root databasename
Then, convert it using the dbconverter.py script
python dbconverter.py databasename.mysql databasename.psql
It'll print progress to the terminal.
Finally, load your new dump into a fresh PostgreSQL database using:
psql -f databasename.psql
You can learn more about the move which this powered at http://lanyrd.com/blog/2012/lanyrds-big-move/ and some technical details of it at http://www.aeracode.org/2012/11/13/one-change-not-enough/.