HTML PHP CSS Web 2.0

CSSVista is a free Windows application for web developers which lets you edit your CSS code live in both Internet Explorer and Firefox simultaneously.
If you like this, you may be interested in our browser compatibility service, SiteVista. Yes, that’s why this software is free!

Features

* Live CSS editing
* Live rendering in Internet Explorer 6 and Firefox
* Split pane view to see both browsers simultaneously
* Completely free!

http://www.sitevista.com/cssvista/

Resize your browser to various standard resolution sizes.

The Browser Window Resizer is useful for testing different screen sizes. It accurately resizes your browser so you can test to see what a web page looks like in all of the standard resolution sizes.
Supports the 640×480, 800×600, 1024×768, 1280×1024, 1600×1200 resolutions.

Resize the current page via the Context menu, Tool menu or Toolbar button.

Window Resizer for Internet Explorer resize the current page via the context menu (right-click) only.

The Firefox extension Resize the current page via the context menu, tool menu or toolbar button.

http://www.yellowpipe.com/yis/tools/window_resizer/