The Oracle Technical Network (OTN) is the official source for everything Oracle. You can access the online documentation without a user
account but it really is worth signing up. Access to OTN is completely free and in addition to documentation and software downloads, you
can find tutorials, white papers, Oracle Magazine, and more.
Software
The free version of Oracle is Oracle 10g Express Edition (XE). Oracle 11g is the current production release for the Oracle Standard and
Enterprise versions. The majority of the Oracle specific information on this site will concentrate on Oracle XE.
You can download Oracle XE by logging into OTN and navigating to Download->Database. Scroll down to Oracle Database 10g Express
Edition and choose the Windows or Linux version.
To download Oracle Standard or Enterprise, download Oracle 11g or 10g release 2 for your operating system.
Documentation
For documentation, navigate to tahiti.oracle.com. Tahiti is a set of quick links to online documentation. Click the link that
corresponds to the version of Oracle that you are running.
Support
Metalink
Metalink is a paid support option from Oracle. When you purchase and Oracle license, you also purchase maintenance and support. If you
have purchased a license, you can navigate to metalink.oracle.com to access metalink. As this site is mainly focusing on free options, I
will not get into the details of metalink.
Forums
If you are using XE and do not have a license, there are plenty of support options for you. OTN also hosts the Oracle XE user forum in
addition to forums for SQL, PL/SQL and most other database topics. You can get to these forums by navigating to forums.oracle.com.
The Oracle XE forum is at http://forums.oracle.com/forums/forum.jspa?forumID=251&start=0 but before you can access it you must
register at the XE registration site: http://www.oracle.com/technology/xe/registration
The forums are actively monitored by many Oracle employees as well as many very knowledgeable Oracle users, programmers and DBAs.
In addition to the Oracle forums, there are many others available should you prefer to spend your time elsewhere.
DBA Village, http://www.dba-village.com, is a fairly active forum. I like it for the weekly polls.
ITToolbox.com, the site where I blog, also contains many groups that cover Oracle. You can access the groups at
http://oracle.ittoolbox.com/groups/
Blogs
I find blogs to be the best source of general reading about a database. Concepts manuals are good for getting started and forums are
good for asking questions but blogs cover what people are thinking.
My blog, An Expert's Guide to Oracle Technology, is at http://blogs.ittoolbox.com/oracle/guide. I primarily cover Oracle topics but
I am known to go off topic as well as cover other technologies.
Oracle Blogs, http://blogs.oracle.com/, is a list of Oracle blogs.
You can also access an aggregator such as the Oracle News Aggregator, http://orana.info/. I think ORANA is just about the most complete
aggregator available.