You can use Javascript to create a button that when pressed will provide a link to a specific URL.
Copy the following Javascript function into the Head of your HTML page :
<SCRIPT LANGUAGE="JavaScript">
<!-- Author : Matt Hawkins -->
<!-- Site : http://www.mattsbits.co.uk/ -->
<!-- Begin
function GoToURL(sURL) { window.location = sURL; }
// End -->
</script>
<form>
<input type=button value="Button Link" onClick="GoToURL('http://www.example.com/');">
</form>