use URI::Escape;

my $location = "http://www.google.com/sorry/?continue=http://www.google.com/search%3Fq%3Dperlmonks";

my $new_location = $location;
$new_location =~ s/.*\/sorry\/\?continue=(.*)/$1/;
$new_location = uri_unescape($new_location);

print "   $location\n=> $new_location\n";

__END__
   http://www.google.com/sorry/?continue=http://www.google.com/search%3Fq%3Dperlmonks
=> http://www.google.com/search?q=perlmonks