For viewing the Windows Phone 7 marketplace, you need to have the Zune software installed on your desktop and connected to the phone. Phone7Market is another free app for Windows PC which allows you to view, download and deploy apps available from the marketplace on your phone.

Requirements:

• Windows Phone 7 device (unlocked) or emulator
• Windows PC with Microsoft .NET Framework 4
• It should require the Windows Phone SDK because the dependency of Microsoft.Smartdevice.Connectivity.dll assembly

The app will show only the free items from the marketplace. More details and download available here.