Moodle.org has a great resource for any Moodle site administrator that answers over 40 frequently asked questions.
Answers range from getting locked out of a Moodle administrator account, PHP errors, to upgrade issues. The wealth of information is searchable and accessible to anyone (though you may want to register at Moodle.org for greater access to forum help and the community).
The answers to most questions here relate specifically to Moodle 1.9.x. Of course some of these answers will apply to earlier versions (e.g. 1.7 and 1.8). We will not mention Moodle 2.0, which is due for release some time in late 2010.
This is an accumulation of information from Forums and other Moodle documentation to save you time in finding things out. Thanks to a lot of people who have been contributing without realizing it.
[for additional information visit: http://docs.moodle.org/en/Beginning_Administration_2_FAQ ]