All sw downloads from oracle:
http://www.oracle.com/technology/software/index.html
documentation for 11g:
http://www.oracle.com/technology/documentation/database.html
documentation for 10g release 2:
http://www.oracle.com/technology/documentation/database10gr2.html
documentation for SQL - Developer:
http://download.oracle.com/docs/cd/E12151_01/index.htm