SCREENALICIO.US
A useful site for designer reference: It contains more than 9700 screen
shots of web sites. They can be classified by not just keywords but also
by colors.
Button
collection
Good for getting inspired by many types of fun buttons and simple designs.
WC3 Markup Validation Service
This service is the cornerstone of making sure that sites meet validation
standards.
CSS Zen Garden
Needless to say, this is the most famous site about CSS. Very interesting
tool for seeing various designs using different CSS.
CSS import
A web design gallery with XHTML and CSS. They have many free
XHTML/CSS templates too.
CSS Reboot
The CSS Reboot is a community event for web professionals and enthusiasts.
Max Design
A site with a lot of CSS tutorials. Each tutorial has
sample and actual CSS source code.
Position Is Everything
A site about problems with CSS that occur with mainly IE and
other browsers, and suggestions for fixing them.
Lightbox2
Lightbox is a simple, unobtrusive script used to overlay images
on the current page. It works on all
modern browsers and is very easy to implement.
Prototype
Prototype is a JavaScript Framework that aims to ease development of
dynamic web applications.
script.aculo.us
script.aculo.us
provides an easy-to-use, cross-browser user
interface with JavaScript
libraries to aid in the construction of web sites and web applications.
ThickBox
A webpage UI dialog widget written in JavaScript on top
of the jQuery library. Its function
is to show a single image, multiple images, inline content, iframed content,
or content served through AJAX in
a hybrid model.
browsershots.org
A v ery useful site to check the look of your site with various OSes,
browsers and versions. Useful for checking cross-browser designs.