Dual posting (facebook & twitter) from facebook app

I'm working on a facebook app for someone and they would like the ability to edit photos on both the users facebook & twitter profiles (kinda similar to twibbons). This all needs to be done from within facebook however.

Now, I'm fairly sure I can handle the facebook element of this ok, but it's the twitter part that has me stuck. Would it be as simple as running an oauth script in the iframe and asking for twitter access - or is this disallowed?

Any tips would be much appreciated.

p.s. There are some similar sounding questions I have looked over, but nothing really close enough :)

Twitter does not allow itself to be used through an iframe so you will either have to open a popup to Twitter and have it callback to your Facebook page (I'm not sure how or if you can access URL parameters from a canvas page) or have it callback to your own server before closing.