If you do any work on your website yourself or on your clients website, one of the best free tools I use is Firebug for the Firefox browser. This tool allows you to edit websites in your browser window without having real access to the website and it’s code.
You can make CSS changes, layout changes, html changes and depending on how good you can code, you can almost change the whole look and feel of a website in your browser. Then as you make these changes, you just make note of the new code that you altered and replace it with the real code.
The beauty of using a program like this is you can make changes to a website without screwing up the real website by accident until you exactly know what changes you want to be permanent.
Once you turn on firebug, a box will appear in your browser and as you move your mouse around on a webpage you will see all the code that is related to that particular item. Once you have the item that your want to inspect or alter, click on it to freeze the code from changing when you move the mouse so that now you can edit it.
I can’t recommend this tool enough for anyone wanting to edit their own sites or their clients sites.