Can't Send Mail in Snow Leopard? Try this

Upgraded my Macbook from Leopard to Snow Leopard on Saturday, and all seemed to be well until I couldn't send emails from Mail.app this evening. A google search revealed that others seemed to be having the same problem, but one of the fixes outlined on the Apple forums seems to have done the trick.

1. Close Mail.app if it is open.
2. Open Finder, and go to your user folder, then Library (that is, the Library folder for your user, not the system-wide one).
3. Rename the "Mail" folder to something else.
4. Re-open Mail.app. It should tell you that it needs to import mailboxes. DO NOT click Continue just yet!
5. Go back to the Finder window, and rename the Mail folder back to "Mail" again.
6. Switch back to Mail.app, and now click Continue.
7. Mail should reimport your messages, and you should now be able to send email again just fine!