Ninject-prism-ext is a project mainly written in C#, it's free.
A Ninject Ext to be used with prism rather than using Unity or MEF
Prism.NinjectExtension
This extension is for use with the Microsoft.Practices.Prism library.
The current version requires the following:
Supports:
To use:
I plan to update this for WP7 apps (if possible)