All this assumes that your email system is already delivering mail correctly before you start using spamassassin. If not then get it working before playing with spamassassin and procmail.
> Do I still have to have it set in geek mode?
You can use Normal (your rules are controlled by user-manager procmail web interface) or you can use Geek mode where all rules are controlled by manual command line intervention and not by the web panel.
> Do I have to set all the spam rules myself.
The spam rules are part of spamassassin, just set the spamassassin config as you want it, plus the white & black lists of course.
> DO I have to set it now to get mail off my server rather than
> log into my pop accounts?
Its your choice, if you want POP or IMAP, I don't think using spamassassin changes how you can collect your mail, although if you use IMAP it can direct the spam message to a "junkmail" folder (if enabled), whereas if you use POP the spam message is just delivered as usual to your user account. Then you can use a procmail rule to filter the spam messages if you want, this is where it would be good to enable spamassassin to add the word SPAM to each spam message so you can filter on it if desired.
Hope this helps
Ray