What about:

my $data = join '', <DATA>;
$data =~ s/,/ /g;
my @addresses = $data =~ /(\S+)/g;

print join "\n", @addresses;

__DATA__
  foo@foo.com bar@bar.com,   foo@foobar.com 
bar@foo.com , bar@foobar.com
[download]

This should work find as email addresses shouldn't contain a comma.

update: thanks to dws for suggesting to subsitute a space for a comma.

gav^