We know that since a couple of hours (wrote this 16. Jul 2008) we have offered the newest update for MOSS and WSS V3. All the needed information for this Infrastructure Update you can find in the official team blog of the product group.
With our current experience we would suggest the following order to update SharePoint.
Have all needed language packs installed!
Have SP1 installed for WSS and MOSS and for each installed language pack the corresponding WSS and MOSS language pack SP1.
Install language specific updates for WSS build 6317
Install Infrastructure Update for WSS
Install Infrastructure Update for MOSS
Language packs are available: http://www.microsoft.com/downloads/results.aspx?DisplayLang=en&nr=20&freetext=sharepoint+language+pack&sortCriteria=date
All needed information to install Service Pack 1 http://blogs.msdn.com/sharepoint/archive/2007/12/11/announcing-the-release-of-wss-3-0-sp1-and-office-sharepoint-server-2007-sp1.aspx
WSS language packages for build 6317 http://support.microsoft.com/kb/953484
How to download? Please check in the left upper corner:
At the end go through the blog of the product group: http://blogs.msdn.com/sharepoint/archive/2008/07/15/announcing-availability-of-infrastructure-updates.aspx and install the needed update for WSS and MOSS.
Please understand that an update of a complex server application is not that straight forward you experienced with Office client applications. It will be a small project.
The language specific WSS hotfix package with build 6317 (KB 953484) is available in all needed languages.
The MOSS Infrastructure Update contains also language specific updates.