Following are some useful websites that I use in my daily work.
Oracle Technology Network (OTN) Forum: An online community about Oracle database and tools like Oracle Forms, Oracle Reports, Oracle APEX, Oracle BI and so on
Oracle Application Express (APEX): (Oracle APEX, previously named Oracle HTML DB) is a software development environment based on the Oracle database. One of my projects (e-oncologist.com) was developed using Oracle APEX 4.1 and it is listed in Oracle APEX community website
W3 Schools: Web development tutorials and references.