The 9 best (and free) cross-browser testing tools

One common problem for web developers is how to test their sites with the different versions of browsers and platforms. Because IE is often the most troublesome, I start with those:

• Internet Explorer Application Compatibility VPC Image: Virtual PC VHD files with the browser preinstalled. A Windows-centric solution, but provides the most comprehensive testing solution. To use, you'll need the free Virtual PC app; then create a new VMC and point it to one of the downloaded VHD files above.
  
• MultipleIE: Another Windows-only tool, which provides a way for IE3 IE4.01 IE5 IE5.5 and IE6 to run on the same box. I've had some limited success with this; the browsers can be very temperamental (that is, they can crash without notice).
• Spoon Browser Sandbox: Run different versions of browsers from the web without having to install them on your machine. Though I've not yet used Spoon, it holds great promise.
• Adobe BrowserLab: Upload your pages securely to this Flex app and view snapshots of what they look like on different browsers. This tool is built into Dreamweaver CS5 and holds great potential for easing the testing process.
• BrowserShots.org: Free and comprehensive alternative to BrowserCam, generates screenshots of your design in an incredible list of browsers and platforms. Because the tool is free, a lot of developers use it. For best results, limit your testing to just a few browsers; this speeds up the results.
• IETester: Free browser for testing pages against IE 5.5 - 9. It's relatively new but holds promise.
• NetRenderer: Choose IE version and enter a URL -- it's that simple.
  
• iPhoney: Free tool for testing designs on the iPhone.
  
• iPad Seek: Online tool to test your designs on the iPad in a similar fashion to iPhoney.