For instructions - use this link:
Deploying Multilingual Interface http://technet.microsoft.com/en-us/library/cc262108.aspxfor SharePoint 2007
Here is the link for operating system language files:
Windows 2008 R2 OS Language Files (All languages - 2+ Gb download)
This is DVD image - hence either burn it on disc or use the any Virtual Image mount software.
If you do not want all the languages and want to download individual files for OS then use the following link,
(select the language from the drop down first..)
Windows 2008 R2 OS language files - Individual Language download
Now go to the regional - language settings of the OS (from control panel) and select the option to install this language. It will look for the path of the file downloaded. Specifiy that where above files were downloaded.
Next comes MOSS 2007 Language packs:
1. WSS 3.0 Language Pack
2. WSS 3.0 Language Pack SP2
3. MOSS 2007 Language Pack
4. MOSS 2007 SP2 Language Pack
Yes that is correct - you need WSS language files also for MOSS 2007.
The above should be installed in the same order and after each of the 4 steps - run the SharePoint configuration wizard. Do not disconnect from the farm if that options shows up.
I hope this becomes easier in future but for now this is what it is for MOSS 2007.