I'm a little frightened by the eerie similarity between the code posted by tye above and what I worked up after I saw the original post. I post mine here anyways because I don't want to waste it.

I was even planning a comment about sprintf/localtime! The only difference is the way we did the loop.

#!/usr/bin/perl -w
use strict;

my %services = (www => qr/:0050\s/,
                ssh => qr/:0016\s/,
                irc => qr/:1A0B\s/,
                ftp => qr/:0015\s/,
               );
my $date = `date +"%l:%M:%S"`;
my @tcpalive = grep /\b01\s/,`cat /proc/net/tcp`;

while (my($key,$REx) = each %services) {
    $services{$key} = grep /$REx/,@tcpalive
}

open (FILE, "+>/var/www/web/main.txt") or die $!;
print FILE "There are $services{www} web, $services{ftp} ftp, ",
           "$services{ssh} ssh, and $services{irc} irc connections ",
           "to this server as of $date\n";
close FILE or die $!;
[download]

In general, `grep' is your friend. What you had was not at all bad, though, just a little un-Perlish. Seeing -w and strict warms my heart :-)