To do exactly what you asked for, in a non-flexible way...

#!/usr/bin/perl

use Data::Dumper;

my $text = join('', <DATA>);

my %hash = ($text =~ /(\d+)\~\<font color="(#[0-9A-Fa-f]{6})"\>/g);

print Dumper(\%hash);

__DATA__
4~<font color="#FF0000"><b>,</b></font> Some junk
5~<font color="#FF0200"><b>,</b></font> more junk 6~<font color="#FF03
+00"><b>,</b></font>sd
7~<font color="#FF0400"><b>,</b></font> last junk 99
8~<font color="#FF0500"><b>,</b></font>
[download]

[TINPC@perlcabal.com shh]$ su real