John,

What exactly are the high level objectives you're trying to achieve?
If you're capturing data from a form into the DNN DB, then I recommend a module like FormMaster NEXTGEN as it enables you to design the tables you're holding data in. That way - when it comes to exporting the data from your DNN DB, and importing it into your Sharepoint DB, you can specify exactly how that happens.

Without knowing if the DB's are on the same network etc, I can't recommend the best way to achieve your goal, but I usually export from DNN to a csv, and drop it in a location accessible by the receiving DB.

Hope this helps.

Mike.