Sounds it would be easy to create Greasemonkey userscript to do so.
Greasemonkey scripts are launched only on URLs matching the expreession you provide (so you can write sth like "http://dzone.com/*), and they are executed once page is loaded (top be more more detailed: when DOMContentLoaded event fires).
Writing a script should be easy with just plain JavaScript and XPath.
You need to read some value by XPath like you say, and then to do the redirect, set window.location = ....
If I understood you correctly, you can use the following code - works for me in Firefox 7.0.1 / Greasemonkey 0.9.11
// ==UserScript==
// @name Dzone Automatic Redirect
// @namespace userscript_dzone
// @include http://www.dzone.com/links/rss/*
// ==/UserScript==
var XPathTools =
{
getElementByXpath : function(xpath, referenceNode)
{
var xPathResult = document.evaluate (xpath, referenceNode, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null);
return xPathResult.singleNodeValue;
}
};
var xpath = "//div[@id='linkDetails']//div[@class='ldTitle']/a";
var url = XPathTools.getElementByXpath(xpath,document);
window.location = url;