Description
* Build applications for Windows Client, Web, Microsoft Office system, .NET Framework, SQL Server, and Windows Mobile with integrated drag-and-drop designers.
* Ensure application correctness easily with integrated unit testing.
* Design complex Office Ribbons with the Ribbon Designer and the provided Ribbon controls.
* Build applications to target SQL Server by using Microsoft Visual Basic® or Microsoft Visual C#® code directly within the database.
* Developers can leverage rich design-time support for Microsoft SQL Server Compact 3.5 in device projects.
* Add an MSDN Premium Subscription or MSDN Professional Subscription to Visual Studio 2008 Professional Edition for access to a wide variety of resources and technical support options.

And of course, Professional has all the features of Visual Studio Standard including:

* Build applications using the latest Web technologies with improved support for AJAX and Web controls with the Microsoft AJAX Library.
* Build Web applications easily with support for cascading style sheets (CSS), JavaScript, IntelliSense®, and a split code/design view.
* Build data-driven applications smoothly with LINQ, a set of language extensions to Visual Basic and Visual C#.
* Manage and build applications that target multiple versions of the .NET Framework with a single tool.
* Build stunning user experiences with integrated designers for Windows Presentation Foundation.
* Create connected applications using new visual designers for Windows Communication Foundation and Windows Workflow Foundation.
* Simplify the design, development and debugging process with handy editor features, such as Edit and Continue and IntelliSense.

Requirements
To install Visual Studio 2008 Professional Edition, you need: Software requirements: 32 bit OS: Windows® XP Professional with Service Pack 2 installed, Windows Server 2003, or Windows Vista 64 bit OS: Microsoft Windows Server® 2003 with SP1, Standard x64 Edition (WOW) * Microsoft Windows Server 2003 with SP1, Enterprise x64 Edition (WOW) * Microsoft Windows Server 2003 with SP1, Datacenter x64 Edition (WOW) * Microsoft Windows Server 2003 R2, Standard x64 Edition (WOW) * Microsoft Windows Server 2003 R2, Enterprise x64 Edition (WOW) * Microsoft Windows Server 2003 R2, Datacenter x64 Edition (WOW) * Microsoft Windows XP Professional x64 Edition (WOW) * Windows Vista Client software prerequisites: Internet Explorer® 6.0 with Service Pack 1, Microsoft Office 2003 with Service Pack 1 or Microsoft Office 2007, MDAC 9.0, .NET Framework 2.0 Hardware requirements: Minimum: 2.0 GHz CPU, 512 MB RAM, 8 GB HDD Recommended: 2.6 GHz CPU, 1 GB RAM, 20 GB HDD