The operations team reports that the sandbox outage that continued to impact customers today is now resolved. The ongoing upgrade and migration work is complete. Jeff posted an alert on the issue earlier and has been posting regular updates on the blog: http://community.microsoftadvertising.com/blogs/api/archive/2010/01/18/sandbox-environment-down-for-upgrade-today-monday-1-18-2010.aspx
Please let us know if you encounter issues or have questions.
thanks
Chris