From the Microsoft Online Services Notifications feed:
Microsoft Online Services is deploying a Service Update to production data centers in the Asia/Pacific region, and the update is planned for the Asia/Pacific production data centers for the following dates and times:
Friday, June 25, 2010, 22:00 GMT+8 to Saturday, June 26, 04:00 GMT+8
Saturday, June 26, 2010, 22:00 GMT+8 to Sunday, June 27, 04:00 GMT+8
Work in the deployment of this Service Update will have minimal to no impact to availability of the services, except for SharePoint Online, which may be unavailable during the maintenance windows.
Microsoft Online Services Team