Well, there could be lots of things using the name "Oracle", but generally it refers to the relational database system.
Typically, programming Oracle stored procs and packages is done in a language called PL/SQL, but in newer versions of Oracle you have the option to use other languages as well, as far as I understand. I have only used PL/SQL.
Oracle also provides a number of development tools for writing applications, but I have not used these.
You can get a personal copy of Oracle for free (or at least you used to be able to do this) that you can install on your computer. The version I used installed easily - but it is a pretty big app and takes a bit of time to install. I suggest it would be best to find someone near you who has dealt with Oracle DB to give you a little assistance. Perhaps there is an Oracle User Group, or a more general Database User Group of some type in your area where there are plenty of helpful geeks to assist.
There are numerous books and tutorials available, and courses, and etc. But essentially, a good understanding of ANSI SQL and the way it is implemented in Oracle is the place to start. If you can't get your hands on Oracle to learn with, you can learn SQL with almost any modern db - such as Access, Sql Server, MySql, and of course, Oracle.
Woody Z http://www.learntoprogramnow.com