To speed up your installations of MOSS there is a way to add patches, service packs and updates to the MOSS media.
Copy the MOSS media to the local hard drive for example c:\moss.
Download your updates for MOSS from the Microsoft Website.
Save each of the files to a folder for example c:\updates. On each of the files run the downloaded executable from the command prompt and enter the parameter /extract:updates.
For example: wssv3sp1-kb936988-x86-fullfile-en-us.exe /extract:updates
Links below are for x86 architecture:
The 2007 Microsoft Office Servers Service Pack 1
http://www.microsoft.com/downloads/details.aspx?FamilyID=ad59175c-ad6a-4027-8c2f-db25322f791b&displaylang=en
Windows SharePoint Services 3.0 Service Pack 1
http://www.microsoft.com/downloads/details.aspx?FamilyID=4191a531-a2e9-45e4-b71e-5b0b17108bd2&displaylang=en
Infrastructure Update for Microsoft Office Servers
http://www.microsoft.com/downloads/details.aspx?FamilyId=3811C371-0E83-47C8-976B-0B7F26A3B3C4&displaylang=en
Infrastructure Update for Windows SharePoint Services 3.0
http://www.microsoft.com/downloads/details.aspx?FamilyId=256CE3C3-6A42-4953-8E1B-E0BF27FD465B&displaylang=en
Running the /extract parameter will create a subfolder called c:\updates\updates and add all the extracted files to this directory. Once you have extracted all files to the directory copy them to the MOSS media folder c:\moss\x86\updates folder or c:\moss\x64\updates (remembering to download the x64 patches as apposed to the x86 links provided above).
Once all the updates have been added to the folder run setup.exe and this should automatically install the updates as part of the initial install.
To check these have installed correctly after the installation has completed go to SharePoint Central Administration-Operations-Servers in farm and you will find the version number here which will be something similar to 12.0.0.6219.
Penny Coventry has a great blog on how to find what version of MOSS your farm you are running, see link below:
http://www.mindsharpblogs.com/penny/articles/481.aspx
Hopefully this should save you some time!
***UPDATE 26/05/09***
Service Pack 2 has now been released and can be found at the following links:
The 2007 Microsoft Office Servers Service Pack 2
http://www.microsoft.com/downloads/details.aspx?FamilyId=B7816D90-5FC6-4347-89B0-A80DEB27A082&displaylang=en
Windows SharePoint Services 3.0 Service Pack 2
http://www.microsoft.com/downloads/details.aspx?familyid=79BADA82-C13F-44C1-BDC1-D0447337051B&displaylang=en
From further reading there is no indication that Service Pack 2 includes the infrastructure updates so therefore download these files along with the Infrastructure Updates.