Microsoft has released several editions of Visual Studio 2012 Express. Depending on your needs, you can install and use anyone of them side by side.
Visual Studio Express 2012 for Windows 8
Visual Studio Express 2012 for Web
Microsoft Visual Studio Express 2012 for Web is an easy-to-use environment for developing dynamic web and cloud applications. It features a streamlined interface that focuses on providing the tools that you need for creating web applications. Visual Studio 2012 includes full IntelliSense support for HTML5 making it easier to develop conforming web sites. This edition is also the tool for creating cloud applications hosted on Windows Azure after installing Windows Azure SDK. More info here.
Visual Studio Express 2012 for Windows Desktop
You can use Visual Studio Express 2012 for Windows Desktop to build powerful desktop apps in C#, Visual Basic, and C++. You can target client technologies such as Windows Presentation Foundation (WPF), Windows Forms, and Win32. Apps built with this edition may not be published in the Windows Store but can be distributed to users directly via downloads or DVDs. More info here.
Visual Studio Team Foundation Server Express 2012
With Team Foundation Server Express, even the little guys can go big. Up to five developers can access powerful application lifecycle management tools, collaborating and controlling the rise of your application, just like any large organization. More info here.
Visual Studio 2010 Express for Windows Phone
Visual Studio 2010 Express for Windows Phone is a complete development environment for creating Windows Phone applications. Visual Studio 2010 Express for Windows Phone includes features such as a Windows Phone-based design surface, a code editor, Windows Phone project templates, and a Toolbox that contains Windows Phone controls. In addition, Visual Studio 2010 Express for Windows Phone enables you to debug and deploy your applications on a Windows Phone Emulator or a Windows Phone device. VS Express for Windows Phone is included in Windows Phone SDK 7.1.
Note: The Windows Phone SDK 8.0 is built on top of Visual Studio 2012, and will give you the ability to build applications and games that target both Windows Phone 8 as well as Windows Phone 7.5. Windows Phone SDK 7.1 can be installed side-by-side with Visual Studio 2012 and runs on Windows 8. Windows Phone SDK 8.0 Preview is available at the Microsoft Connect site until Monday, September 17, 2012 5pm PDT.
Update: Visual Studio Express 2012 for Windows Phone
The Windows Phone SDK 8.0 is a full-featured development environment to use for building apps and games for Windows Phone 8.0 and Windows Phone 7.5. The Windows Phone SDK provides a stand-alone Visual Studio Express 2012 edition for Windows Phone or works as an add-in to Visual Studio 2012 Professional, Premium or Ultimate editions. After installation, you can try this product for up to 30 days. You must register to obtain a free product key for ongoing use after 30 days.
Developers who need features beyond what the express editions offer should consider one of Visual Studio 2012 editions – Ultimate, Premium, Professional, Test Professional, and Team Foundation Server. You can find a comparison of these editions here.