There are issues with Postgres on Mac OS X Lion because it comes with its own Postgres instalation.
Here are the steps I took to make my custom postgres instalation to work:
Delete the existing postgres user with the following command:
sudo dscl . delete /users/postgres
- Recreate postgres user in the system preferences (name it postgres, and preferably chose the postgres123 password)
- Download and install Postgres 8.4 as you would normally do (http://www.postgresql.org/download/macosx)
Alternate installation if you have trouble building you can find here.