We justs submitted our project to the Social Actions' Change the web challenge!
Very curious how this idea will mature. We started programming on the open social widget last week and are making ourselves aquinted with the API's we're going to use.
Here is a design process screenshot of the actual widget:
And here is a design of the users "Add a donation" section:
Let me know of any ideas you have concerning this scenario. Maybe you know of other API's that could provide useful extensions or maybe you have ideas to make the interface better. Any help is appreciated as were just getting started.