And with minor modifications, this is also a valid shell script, for those on UNIX:

Weeellllll ... {G} ... with MAJOR modifications and wrapping it in a shell function wrapper, so it is available at every login w/o regard to PATH location, this idea becomes:

 # (ba)sh function wrapper for Perl code. "perltest" is admittedly NOT
+ a good name ;-)
perltest () 
{ 
    perl -e'
    my$modn = my$mod = "'$1'";
    $mod =~s@::@/@g; $mod.=q[.pm];
    die ("module $modn not installed.\n",$@) if
       ! eval {require qq[$mod];};
    my $modv = defined ${$modn.q[::VERSION]} ?
       ${$modn.q[::VERSION]} : q{[version undefined]};
    my$numtyp= (2 > $modv =~tr/.//) ? "%s" : "% 6d";
    printf "  %-*s $numtyp in %s\n",
      length($modn) > 30 ? 5+length($modn) : 15+length($modn),
      $modn, $modv, $INC{$mod};
    ';
    return 0
}
[download]

I use this so often, sometimes several times a day, that the extra elaboration has proven well-worth it to me.

-- 
Now, 2004: The 3 least meaningful terms in online jargon are:
  troll   flame   rant
These used to mean something; but then they were highjacked by the kind of
inferior intellects who, when faced with a more erudite opponent employing
superior arguments (or simply hanging in there with a disagreeable
contention), abuse these terms as merely another form of name-calling. ;-)

I like

    perl -MCPAN -e 'CPAN::Shell -> m (shift)' MODULE
[download]

which not only gives the installed version number, but also the version number of the newests version on CPAN.

Abigail

Nice one. But you need to know what you're looking for. For example:

$ perl -MCPAN -e 'CPAN::Shell -> m (shift)' DateTimeCPAN: Storable loa
+ded ok
Going to read /Users/liz/.cpan/Metadata
  Database was generated on Fri, 13 Feb 2004 01:50:02 GMT
Module id = DateTime
    DESCRIPTION  A complete, easy to use date and time object
    CPAN_USERID  DROLSKY (Dave Rolsky <autarch@urth.org>)
    CPAN_VERSION 0.20
    CPAN_FILE    D/DR/DROLSKY/DateTime-0.20.tar.gz
    DSLI_STATUS  bmpO (beta,mailing-list,perl,object-oriented)
    INST_FILE    (not installed)
[download]

is a module that I don't have installed: CPAN has 0.20. Whereas:

$ perl -MCPAN -e 'CPAN::Shell -> m (shift)' ifdef   
CPAN: Storable loaded ok
Going to read /Users/liz/.cpan/Metadata
  Database was generated on Fri, 13 Feb 2004 01:50:02 GMT
Module id = ifdef
    CPAN_USERID  ELIZABETH (Elizabeth Mattijsen <liz@dijkmat.nl>)
    CPAN_VERSION 0.03
    CPAN_FILE    E/EL/ELIZABETH/ifdef-0.03.tar.gz
    MANPAGE      ifdef - conditionally enable text as code within pod 
+sections
    INST_FILE    /usr/local/lib/perl5/site_perl/5.8.3/ifdef.pm
    INST_VERSION 0.03
[download]

shows that I have the "ifdef" module installed. Note that both the "CPAN_VERSION" as well as the "INST_VERSION" are shown now.

Liz