No, /WebService is the virtual URL created by mod_perl; browsing to that URL will trigger SOAP::WSDL::Server::Mod_Perl2's response handler.
SOAP::WSDL needs to be installed somewhere that mod_perl can find it; this means it needs to be in a path in the @INC that mod_perl uses. As a matter of general principle, I'd suggest not installing it in your DocumentRoot. Note that @INC can be modified; see http://perl.apache.org/docs/2.0/user/intro/start_fast.html#Configuration for a quick start on mod_perl. I'd suggest familiarizing yourself with mod_perl's basic operation a bit. The basics aren't too hard, and learning them will save you some headaches later. Coding under mod_perl is *almost* like writing a script, but you need to be a little careful since the perl interpreter doesn't exist between requests.