Hi,
The easiest way to get the hypertext is to press the paperclip symbol that should be in your reply box. This bit:
It then brings up this:
You post the Web address directly copied from the product page in the top box and pop whatever blue text you want to appear in the lower box.
Feel free to practise any forum tools you fancy having a play with here or in The Sandbox 
ETA Doh 
@SexInTheCity got there first! 
We are in agreement though thank goodness 