Accepting data from URL Parameters

I appologize for what may be a newbie-like request, but I have not been able to find this information in the PHP documentation. If I were to have a link on an HTML page such as the following: http://www.foo.com/myscripts/myscript.php?Value1=value&Value2=value How can I retrieve those values in the script? Should I construct the link differently? Is there a completely different method I'm missing altogether? Thanks so much in advance for any help you could provide! Jared