Here is a simple example for Sterling and the Hong Kong dollar (I didn't have Taiwanese dollar in my version of Excel):

    #!/usr/bin/perl -w

    use strict;
    use Spreadsheet::WriteExcel;

    my $workbook  = Spreadsheet::WriteExcel->new('currency.xls');
    my $worksheet = $workbook->add_worksheet();


    my $pound_sterling   = $workbook->add_format(num_format => '£#,##0
+.00');
    my $hong_kong_dollar = $workbook->add_format(num_format => '[$HKD]
+ #,##0.00');

    # You can also use this slightly more explicit format for Sterling
+:
    # [$£-809]#,##0.00

    $worksheet->write('A1', 1.23, $pound_sterling);
    $worksheet->write('A2', 1.23, $hong_kong_dollar);
[download]

--
John.

Thanks jmcnamara, I overlooked it in the documentation.
In Spreadsheet::WriteExcel, search for the set_num_format under the CELL FORMATTING section. You find this...

$format04->set_num_format('$0.00');
$worksheet->write(3,  0, 49.99,     $format04);    # $49.99

$format05->set_num_format('£0.00');
$worksheet->write(4,  0, 49.99,     $format05);    # £49.99

$format06->set_num_format('¥0.00');
$worksheet->write(5,  0, 49.99,     $format06);    # ¥49.99
[download]


regexes