The mail services provided on the SP are the same as the ones provided on a standard AIX environment. From the mail service point of view, the SP can be viewed as any other cluster of nodes. If you need to provide mail access on the nodes, the same configuration rules and techniques used for the rest of the LAN or intranet apply. Since this topic is not SP specific, but rather AIX specific, see the following documents for additional information:
Search for the mail overview chapter.
Search for mail in the table of contents.
Besides the IBM publications on the subject, several other books discuss all pertinent subjects like SMTP, UUCP, TCP/IP, POP, IMAP, DNS, NFS, NIS, and even configuring popular E-mail software packages.