Right, you want to post a link to a great website - http://www.hot-chicken-soup.co.uk
Normally It's as simple as just typing in the address in your post (see it did it just there):
however if the URL is very long this may lead to the page size being stretched - which is a pain when reading the rest of the posts in a topic. In this case you can use this syntax instead:
<blockquote><code>[url=<font color="red">http://www.hot-chicken-soup.co.uk</font>]<font color="blue">soup link</font>[/url]</code></blockquote>
The <font color="red">red</font> bit is where you put the link address/URL and the <font color="blue">blue</font> bit is the text you want displayed for that link. The example above would end up being displayed as:
<blockquote><a href="http://www.hot-chicken-soup.co.uk">soup link</a></blockquote>
If you put your mouse over the "URL" button when composing a message it'll remind you of the syntax.