I don't get FirePhp FirePhp is an extension for the Firefox add-on Firebug.
I don't get why this should be used at all. How can this tool give me more than your everyday PHP debugger? Seriously? I don't understand how to implement this, can someone please explain... video with narration perhaps?
In deep narrator voice FirePHP, with a little work, lets you send information to the firebug console. It can be rather detailed. see http://www.christophdorn.com/Blog/2009/04/03/how-to-integrate-firephp-for-ajax-development/ for the best info on it. is it better than other debugging tools? debatable. Honestly, I don't really use it much.
According to what I've read about it: Say you want to know the value of some random variable in your PHP script. Your server sends a special header containing that info, and Firebug reads it. The advantage of the process is that the actual response (headers excluded) is the same, so you can keep the same response handling code. I guess it makes Ajax'd PHP scripts easier to debug.
The killer app for firephp is debugging AJAX calls. The PHP sends back the debugging info in the response headers, which the firephp plugin then displays, appending to the console.
So, you have your client side javascript output what it's doing, and you can see the PHP side output what it's doing, and you can see a co-mingled, ordered 'trace' (for lack of better terms) of the interaction between your javascript and your php.
I did a quick presentation last month on how I use firephp last month. It's not the video you want, but... http://links.creuzer.com/chfgq