The link href should be the full absolute URL to the stylesheet. Something like:
<link href="http://myserver.mydomain.com/wp-content/themes/urbanwords/style.css" media="all" type="text/css" rel="stylesheet">
If you paste the href into your browser's address bar and hit return, you should see the stylesheet code in the browser window. For example, here's one I did earlier:
If your stylesheet doesn't show up you need to check all the URL parts to find out which bit is wrong.
Couple of other things to check:
- Your stylesheet is called style.css
- The proper comment block appears at the top of the stylesheet