Get a webhost!
After you've created a webpage, you need to put it online if you want other people to see it. This is called "hosting" or "web hosting", because a company hosts your website on their web server.
Use freewebspace.net to find a free host. Or, if you'd like to pay for webspace, which usually gets you more space and more features, I recommend affordableHOST ($45/year for 50 megabytes of space) or powweb ($94/year for 200 megabytes of space).
Once you find a host, you transfer or "upload" your HTML pages to the host's webserver. You'll do this through a webpage on the host's site, or with an FTP program -- it depends on the host. Once your pages are uploaded, you can access your site by a web address like http://www.powweb.com/mysite. If you want a "domain name" like www.mysite.com, you need to pay for one. Both affordableHOST and powweb can sell you a domain name. As of summer 2002, they cost about $15 per year.
Note that if you want to write Perl/cgi scripts for your website, your webhost must allow this. Many free ones do not! So if you're looking for a free webhost, make sure the one you use will give you a /cgi-bin/ directory to put your own perl scripts into.