++ Works great, I could have used this on some past projects. It's surprising the doubleclick bug has never been fixed. Here's my rough cut at a module version of your code, called in more of a Perl Tk style.

package Tk::Doubleclick;

require Exporter;

our @ISA = qw(Exporter);
our @EXPORT = qw(bindClicks);

sub bindClicks {

    my %arg = @_;
    my $btn = delete $arg{-widget};
    my $delay = delete $arg{-delay} || 300;
    my $args1 = delete $arg{-single};
    my $args2 = delete $arg{-double};
    my $clicked = delete $arg{-button} || 'left';

    my %btnTable = (
        left => 1,
        center => 2,
        right => 3
        );
    
    my $mousenum = $btnTable{$clicked} || $clicked;
    $mousenum = 1 unless ($mousenum =~ /^[123]$/);

    my $single = $args1;
    if (ref $args1 eq 'ARRAY'){
        $single = shift @$args1;
    }else{
        $args1 = [];
    }

    my $double = $args2;
    if (ref $args2 eq 'ARRAY'){
        $double = shift @$args2;
    }else{
        $args2 = [];
    }

    my $nclicks = 0;
    my $c_cmd = sub {
        ++$nclicks;
        $btn->after($delay => sub {
            my $count = $nclicks;
            $nclicks  = 0;
            if ($count > 1) {
                $double->(@$args2);
            } elsif ($count == 1) {
                $single->(@$args1);
            }
        });
    };

    my $button_name = "<Button-$mousenum>";
    $btn->bind($button_name => $c_cmd);
}
1;
=head1 NAME

Tk::Doubleclick - Correct handling of single vs double click callback 
+bindings

=head1 SYNOPSIS

  use Tk::Doubleclick;

  bindClicks(
     -delay => 500,
     -widget => $button_widget,
     -button => 'left',
     -single => [ \&callback, @args ], # with arguments
     -double => \&callback,            # without arguments
     );

=head1 OPTIONS

=over 5

=item -delay

Maximum delay time detween clicks in milliseconds. Default = 300.

=item -widget

Widget to bind to mousebuttons. 

=item -button

Mouse button to bind. Options are left, center, right, 1, 2, 3. Defaul
+t = left.

=item -single

Single click callback. To include arguments, use array reference.

=item -double

Double click callback. To include arguments, use array reference.

=back

=cut
[download]

Update: fixed typo