Just found that Adobe just launched a preview of Adobe Browser Lab a tool for cross-browser testing of web pages and apps as it would appear on different browsers and operating systems,and it let’s you define browser sets for testing and set 1-up view 2-up view or onion-skin view, check Adobe Labs for more info or visit Adobe BrowserLab

BrowserLab provides web designers exact renderings of their web pages in multiple browsers and operating systems, on demand. BrowserLab is a powerful solution for cross-browser compatibility testing, featuring multiple viewing and comparison tools, as well as customizable preferences. Since BrowserLab is an online service, it can be accessed from virtually any computer connected to the web. Also, Adobe Dreamweaver® CS4 software users have access to additional functionality such as testing local and active content.
Features
Supported Browsers and Operating Systems
- Firefox 2.X and 3.X (Windows XP and Mac OS X)
- Internet Explorer 6.X and 7.X (Windows XP)
- Safari 3.X (Mac OS X)
Viewing and Diagnostics Tools
Screenshots can be viewed in a single view, side by side view, or as an overlay view with variable transparency. Each viewing option features a zoom function.
Browser Sets
Browser Sets allow designers to customize, edit, and save a combination of browsers to test.
Adobe Flash Builder 4 (formely Flex Builder 4 ) and Adobe Flash Catalyst are out on Adobe Labs going to download and try them out before posting a proper review meanwhile more info on Ryan Stewart’s blog and Andrew Shorten’s Tutorial

Flash Builder 4 delivers a long list of new features, plus improvements to many existing features.There are three main themes to this release: developer productivity, designer-developer workflow, and data-centric application development. For an overview of the features included in this first public beta release, please read Tim Buntel’s What’s New in Flash Builder 4 article and watch the new feature videos. As always, the Flex 4 framework is included within Flash Builder, so please also read Matt Chotin’s What’s New in the Flex 4 SDK article.

Adobe® Flash® Catalyst™ is a new professional interaction design tool for rapidly creating user interfaces without coding.
- Transform artwork created in Adobe Photoshop® and Adobe Illustrator® into functional user interfaces.
- Create interactive prototypes with the ability to leverage them in the final product
- Publish a finished project as a SWF file ready for distribution
- Work more efficiently with developers who use Adobe Flash Builder™ 4 to create rich Internet applications (RIAs). Designers use Flash Catalyst to create the functional user experience then provide the project file to developers who use Flash Builder to add functionality and integrate with servers and services.
Go get Flash Builder 4
Go get Flash Catalyst
Flash Builder 4 Standalone Installer
Flash Builder 4 Plugin for Eclipse
Flex Component Kit for Adobe Flash Professional CS4
Flex 4 Test Automation Plug-in
Flash Catalyst Beta
More Adobe Resources:
Learn about Flash Builder 4
Learn about Flex 4 SDK
Working with Flash Builder 4
Grupo W is looking for ActionScript / Flex Developers if you’re interested don’t hesitate and send your CV here’s the Job info:
Company: Grupo W
Location: Saltillo, Coah. Mexico
Position: Flash ActionScript / Flex developer
Information:
Mandatory technical skills:
• 3+ years experience in ActionScript 2.0 or 3.0 for Flash applications integrated with server-side web applications and CMS
• Papervision knowledge
• Experience implementing OOP concepts with ActionScript
• Experience integrating streaming media
• Building integrated data-driven applications
• Source control
Communication skills:
• Outstanding problem-solving and communication skills
• Available to work in-house during work hours – Monday – Friday
• Team player and leadership skills
Ideal additional skills:
• SWF address
• AIR
• Experience in building social networking and community systems, which include context and video tagging, streaming media and other advanced online communication features
Desired additional skills:
• Experience in PHP/MySQL
• CMS experience
To Apply:
Please send a copy of your CV with portfolio and examples of sites directly to rcalderon@grupow.com