For Oracle 9i + 10g (database), there used to be a really helpful script that you could run to validate your environment was correct before you did the install.
Does such a thing exist for 11g does anyone know? Or is the validation finally done by the OUI? If something similar does still exist, please can someone point me in the right direction?
There is an early step in the Oracle install that checks various items and gives warnings if various things are not met.
Check out HJR's GOAL as well. It does a lot of the settings/grabbing packages etc.