I'm rather short on space in my system drive, and was wondering if there's a way to move MSOCache to another drive manually, or with a tool so I can still update my Microsoft Office install without having to find the CDs again.
You would need to copy the entire folder to it's new location, then clear the old folder and replace it with a symbolic link to the new location.
Here is a MSDN post regarding creating symlinks if you want more detail, but briefly in your case you need to do something like the following from a command prompt (that must have Admin privileges) that is currently pointing at the root of your C-Drive.
mklink /D "C:\MSOCache" "D:\New\Folder\For\MSOCache"
I did a bit more digging on my own, and just turned up a blog post about a tool from Microsoft called Local Installation Source. Once you install this tool and run it, it moves the files and handles the registry changes. I'm still working with Microsoft Office 2003, so I don't know if there's a similar tool for Office 2007 or 2010.