Download details: SharePoint Portal Server 2003 Service Pack 1

Yes folks, SP1 for SPS2003 has shipped, and SP1 for WSS.

The WSS Service pack is going to be included as a critical update on Windows Update.

Here are some quick links to more information in KB articles. If they are not working, just wait, they're due to be there 10:00PST/18:00GMT.

SPS fixlist
WSS fixlist
SPS SP 1 must be applied to all servers in the farm
Install of patch incomplete if you install before creating configuration database
Service pack language must match installed language
Error attempting to patch if source files are missing and RTM files were deleted or changed
Installing WSS SP 1 in a farm and how to verify the service pack installed correctly
Error browsing sites if a content database could not be upgraded

My advice is make sure you read these carefully first, then install the Service Packs to a development or test machine. Bear in mind, service packs can overwrite customisations, depending how you implemented them, so do a full backup before installing them on your production machines, and be sure to install when there will be no users on in case you need to rebuild. There is no uninstall feature for this download. Good luck!