Email all over the place
 

I recently obtained a dedicated server and I have email in various places:

/root/mbox
/home/admin/mbox
/home/siteadmin/mbox
/var/spool/mail/root
/var/spool/mail/admin
/home/virtual/admin/var/spool/mail

I'd like all mail to go to admin or siteadmin and be able to get new message via POP (or IMAP). Right now POP gets root's mail in spool. Additionally I'd like to combine all the existing email - 'cat' it all together into one file? Also, none of the mail is being moved to mboxs anymore once it's read - it's remaining in spool.

I'm new to configuring mail systems on Linux, but I'm learning all I can about Sendmail, DNS, POP, and IMAP. I'm uncertain whether it's a DNS MX problem, Sendmail configuration, aliases, virtual hosting (site also has Ensim's Webppliance installed but it has been shut down), mail.rc, and/or something else.