Correct, /etc/services, it's the same on BSD and every other UNIX system I have ever used. Actually it's pretty much standard on all TCP/IP based systems, even Windows (except the services file is in a different directory in Windows, NT* systems have it in C:\WINNT\SYSTEM32\DRIVERS\ETC, of course).
You are also right that newer Linux systems are using xinetd over inetd and it's main configuration file is /etc/xinetd.conf but the configuration for each xinetd service is in it's own separate file under /etc/xinetd.d/. The contents of each of those files used to be a single line in /etc/inetd.conf.
Of course many other TCP/IP programs use the /etc/services file. The "netstat" command for instance uses it to turn port numbers into names. If you didn't have the services file there all you would see are numbers. For instance "http" would show up as "80".
[ November 24, 2002: Message edited by: void main ]