This really doesn't have to do with arrays but rather with URLs and how they work. In order to pass along a space in a URL, you have to encode it; then your CGI script (or whatever) needs to decode it back into a space. If you're using CGI.pm (you probably should be), this decoding happens automatically. The *encoding*, on the other hand, is something you have to take care of yourself. It's easy, though:

use URI::Escape;
$department[0] = "Customer Service";
my $url = "http://www.example.com/script.pl?department=" .
          uri_escape($department[0]);
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If you don't have URI::Escape, just use this to encode spaces:

$department[0] =~ tr/ /+/;
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A space can be encoded as either a '+' or '%20'; I'm not sure if the former is actually in the spec or not, but it works.