TL;DR - Too Long Didn't Read Version
BrowserStack Integrated into Visual Studio
From a debug session inside Visual Studio 2012 today with ASP.NET 2012.2 RC installed. Click the dropdown next to your Debug Button, the click on "More Emulators" to go to http://asp.net/browsers and get the BrowserStack Visual Studio extension and three months free service. There's other browsers to download as well, like the Electric Plum iPhone/iPad simulator.
SIDE NOTE: When the VS2012.2 Update is finalized, you'll need to install just it and you'll get the ASP.NET Web Tools as well.
New Online Tools for Modern Sites
Head over to http://modern.ie for a bunch of tools for making cross browser sites easier, including on online site analyzer and downloadable Virtual Machines for any Virtual Platform.
I do a lot of cross-browser testing and I've been on a personal mission to make "Browse With..." and multiple browser debugging suck less in Visual Studio. This has been going on for years.
In 2010, I used PowerShell and hacked together a browser switcher script in VS2010.
My buddy Kzu and friends saw this script, realized it sucked and made things better on VS2012 with their Default Browser Switcher addon.
I worked with Jorge on our team and we delivered a the browser switcher dropdown directly integrated in VS2012. This feature is also in WebMatrix.
Later the iPhone/iPad local simulator from Electric Plum added tight integration with Visual Studio so you can test locally.
But still, it's too hard. There's been some Virtual Machines up on the Microsoft Download Center but it's tedious to dig around and get the one you need.
Today the IE team announced new site at http://modern.ie to make cross-browser testing easier. Even cooler, they launched a partnership with BrowserStack.com to give us all a three month free trial to their hosted browser virtualization service.
Read more: Scott Hanselman