kindles - does pandora radio work on them?

No. It's an E-reader, not an Internet device.

It can have MP3 downloaded and listened to from it.

So you can listen to a music podcast that you downloaded from your computer and transfered to Kindle 3 or any other non DRM mp3 file from your computer.

there is less internet function to Kindle 3 than there is on a BlackBerry Curve.

It is possible to use twitter from a Kindle 3 but it is slower than a computer or smartphone.

If you have the big bucks and want something like a notebook computer you might want to consider the ipad

this might be a better question for a forum about ebook reading devices but I still think it is extremely unlikely to work

No. Although it does have some additional functionality, the Kindle does nothing well except being a fantastic eReader.

If you want a multi-purpose device, look elsewhere.

My mom has one. The internet is really underdeveloped and so it wouldn't work.