We sure have come a long way in a short time! There are a lot of things we haven't gone over yet, but fortunately PostgreSQL has some of the most complete documentation of any open source project, and also a large and well-informed community who are happy to help new and experienced users alike.
By far the greatest resource in your arsenal is the official PostgreSQL documentation, available here:
http://www.postgresql.org/docs/
That page has links for several versions (8.4 through 9.2 currently), both with and without commentary. The documentation itself is quite large. I recommend you glance at the table of contents and just get a feel for the scope of material covered. For deeper study it would be wise to examine sections 2 and 3 on SQL and administration. The SQL commands section is especially helpful. Naturally, Google searches tend to direct you to the documentation. When you do get to the documentation from a search result, make sure to follow one of the version links at the top of the page to get to the right version for you after a search, Google seems to prefer older versions of the documentation for some keywords.
There is also a wiki community available at:
The wiki has a lot of soft documentation such as tutorials, migration advice from, and comparisons with other database systems. It also hosts the official FAQ and a curated list of books and manuals.
PostgreSQL has both free, community-provided support as well as several companies selling commercial support. Joining the pgsql-general mailing list is recommended for general questions and help. There are many other mailing lists for more specialized discussion, you can see a complete list here:
http://www.postgresql.org/community/lists/
You can also get help on stackoverflow and Database Administrators' Stack Exchange:
stackoverflow is usually more appropriate for SQL querying help and other programming-oriented questions while the other is better for query performance optimization and database configuration questions. If you ask your question just right, you'll get an answer in minutes.
Planet PostgreSQL is a blog aggregator at http://planet.postgresql.org/. Subscribing to it will get you a variety of articles about PostgreSQL from various people invested in the community. It's a great way to stay abreast of what new features are coming or hearing interesting tips and advice.