Coding4Fun has released several common controls that you can use while building Windows Phone 7 applications along with the source.

Not only you get common controls that are required for most applications, the source code behind these is also available since the toolkit is available as a CodePlex project. 

Current Coding4Fun Windows Phone Toolkit:

Controls:

• About Prompt
• Input Prompt
• Progress Overlay
• Round Button
• Round Toggle Button
• Memory Counter
• TimeSpan Picker

Abstract Classes:

• PopUp class for things like an Input Prompt that can be GPU accelerated unlike the built in Popup control.

Converters:

• Boolean to Visibility
• String To Visibility
• Themed Image Converter
• Inversed Theme Image Converter
• Visibility to Boolean

Binding Helpers:

• Textbox update

Data Helpers:

• PhoneHelper for getting data out of the WMAppManifest file

Coding4Fun Windows Phone Toolkit