If Linux have a file like AIX: rc.tcpip to setup port services?
/etc/services will show what is available and you can edit for new services.
/etc/rc.tcpip is a script that starts services(sendmail,etc..) using SRC(some might not) on AIX. It is not directly related to /etc/services.
check out the scripts in /etc/init.d
If you want to run some inet services centrally without worrying about the various standalone runlevel startup scripts,etc...you can always use (x)inetd. http://www.xinetd.org/