I used my personal Yahoo email account for testing a Biztalk orchestration which sent emails through the SMTP adapter.  While debugging some connectivity issues, I opened Outlook Express on the dev box (which is running in an image) and configured it to access my Yahoo mail account in order to verify that I had the correct settings.

A while later I returned to Outlook Express and discovered that it downloaded the entire content of my mailbox from Yahoo to the dev server box, and cleared all the messages off of the server. So now the only copy of all my mail from the last 18 months is in Outlook Express on a friggin dev image :(

Does anyone know how to transfer those messages back to Yahoo mail?   Does GMail support any import capabilites?  As a last resort I might import them into Outlook but I would really prefer to have them available online.