Apple Thoughts: Google Email Uploader for Mac

"Mail storage is the organizational conundrum of the early 21st century for many longtime Mac users. On your hard drive, you probably have an e-mail archive literally dating back to the last century, containing a few thousand irreplaceable, keep-forever messages in an ocean of saved detritus. Searching is a pain, but "reorganizing" your archive is a fate worse than death, so you've gamely stuck to your system-until now, when Google Email Uploader for Mac presented a viable alternative."

You can check out the uploader here, but note that there are a couple of "wait, read this before you do it" elements. It doesn't upload to gmail or google mail accounts, only those that are hosted by Google Apps for your domain. And it requires Mac OS 10.4 or higher. But it will upload from Apple Mail, Thunderbird and Eudora, automatically finding the archives and uploading them. If you have more than 500 messages, however, it may take some time (the author noted it would take the program about 69 hours to do it all once he started the process).