If you have specific questions, the FAQomatic is a good place to
look for answers.  It is at
http://cobweb.dartmouth.edu/cgi-bin/cgiwrap/jonh/faqomatic/faq.pl.
If you have a question which isn't answered in the FAQomatic, then
when you do find an answer, you can contribute the question and answer
to the FAQomatic.  Or if there is an answer in the FAQomatic that you
think is incomplete, incorrect or needs clarification, you can
contribute an update.

There are two mailing lists that you should consider subscribing to.
The first, linux-pmac-announce@samba.anu.edu.au, is a low-volume list
used only for significant announcements about powermac/linux, such as
new software releases.  The second, linux-pmac@samba.anu.edu.au, is a
list for discussion of powermac/linux issues and for asking and
answering questions about using powermac/linux (though, if you ask a
question that's answered in the FAQomatic, you mightn't get much
response).  To subscribe to either list, send mail to
listproc@samba.anu.edu.au with no subject and a line in the body
saying

subscribe linux-pmac Your Name

and/or

subscribe linux-pmac-announce Your Name

Replace "Your Name" by the name by which you want to be known on the
list.