There's no shortage of free resources for web development, but finding the right tool for the task can be tricky. Design Junction has collated a list of free web development software which you can sort or filter by category.
The list is broken into four major categories: web design, web development, mobile and SEO. Within each category you can also filter (so in the development category you can look exclusively at AJAX or HTML5, for example). A useful site to bookmark for when you're researching new tools.
Ultimate Free Toolkit for Internet Web Ninjas [Design Junction]