I looked, but didn't find issues concerning links with the exception, it is up to the admin, so here goes. These can be very helpful, I hope you don't mind.
These are a few links I think are applicable to not only the programs included in Xampp, but also some that will be helpful to developers out there. I found them very handy, perhaps you will too.
--Setups/Information--
Developer Shed has quite of few informative articles including setup of Xampp including security.-- http://www.devshed.com/c/a/PHP/Doing-Mo ... in-Part-1/
--Tutorial Sites--
KillerPHP is a nice free video tutorial site for the beginner. Stefan Mischook will guide you from what is programming language to object oriented php. Thanks to merlinsmum for sending me the link which I'll share here.-- http://www.killerphp.com/
--Tools for the browser--
Web Developer's Toolbar (free). Adds a menu and a toolbar with various web developer tools. A fantastic tool for the developer; validation, view block level element's outlines in html documents, view css files and a ton more, all in one plug-in. Highly recommended.-- https://addons.mozilla.org/en-US/firefox/addon/60
Live HTTP Headers (free). Not much you can do with it; but, excellant to show you what is happening under the hood when you bring up any page, you have to check this out.-- https://addons.mozilla.org/en-US/firefox/addon/3829
--Program Manuals/Guides--
Apache-- http://httpd.apache.org/docs/2.2/
PHP Manual-- http://us.php.net/manual/en/
PHP Language Manual-- http://us.php.net/manual/en/langref.php
MySql-- http://dev.mysql.com/doc/refman/5.1/en/
Javascript Guide-- http://developer.mozilla.org/en/docs/Co ... _1.5_Guide
W3C School (for all things web developing)-- http://www.w3schools.com/default.asp
If you can come up with a few good ones - why not list them -- if admin doesn't mind. And if they don't mind, maybe they will make a sticky out of this thread.