WordPress MU

Hi

i have installed and runs fine the WPMU,
Is there any stuff plugins/themes/widgets customization FAQ ?

i.e. which file to change for which parts in my WPMU installed setup <or installable setup>

how to enable/disable the stuff. <like i dont want to have video upload etc in my post, i want "keyword1 keyword2" appear always by defult when user is publish post, <they can remove if they want>

i want "Just another weblog" replaced by user specific stuff + on next line, static caption <which will be there on every user of my WPMU>

any faq/help page is available for all these stuff ?

-Raxit

http://wpmudevorg.wordpress.com
http://wpmututorials.com
http://codex.wordpress.org/Category:WPMU