David,
the course forum news could be a simple and effective solution to notify scheduled maintenance. What do you think?
Btw, some hours ago (2010-08-26 09:55 UTC) I committed a bunch of strings AFTER the maintenace. However, the Italian language pack does not seems to receive the new commits as Moodle keep telling packages are up to date. Among the other strings I committed "enrol_paypal" which is still not updated. Any thoughts?