There may be better ways to do this, but I simply use Win32::OLE to traverse the LDAP hierarchy. This is quick code, but it should point you in the right direction. This will print everything, including a lot of things you probably don't care to see. You could decide whether to look at an object based on its class, and also if it was a class like "user", print out some additional attributes.

use Win32::OLE qw(in);

showObjects("LDAP://[INSERT DOMAIN NAME HERE]","");

sub showObjects {
    my ($path, $space) = @_;
    my $object = Win32::OLE->GetObject($path);
    print "$space $object->{Name} ($object->{Class})\n";
    foreach my $childObject (in $object) {
    showObjects($childObject->ADsPath, $space . "  ");
    }
}
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I can't take credit for this approach—I basically translated a solution in O'Reilly's Active Directory Cookbook from VBScript to Perl. If you have to do a lot of AD scripting, this book would probably be a good investment. It's pretty simple to translate its VBScript code into Perl.