ipopd is your standard default. I'd go for uw-imapd-ssl and ipopd-ssl myself. 
:)

looking at /etc/services should tell you what ports, but:
smtp            25
pop2            109
pop3            110
imap2           143
imap3           220
imaps           993
pop3s           995
ssmtp           465

Set your firewall to allow pop3 and imap2 from localhost only, allow pop3s 
and imaps from the outside world. Some things like webmail need to hit up 
pop3 or imap over the loopback interface, that's the reason for localhost 
only. Everyone else uses SSL. (And do your webmail with apache-ssl, other 
wise you defeat the purpose of allowing only imaps and pop3s.)

-- 
Andrew S. Zbikowski | http://www.ringworld.org
"We can learn much more from wise words, little
from wisecracks and less from wise guys."
--William Arthur Ward