.tar files are just archives where the files and directories are contained in a nice archive.
Let's say you have a distribution at /usr/local/goodstuff
To create the tar file (one example):
tar cvf goodstuff.tar /usr/local/goodstuff
This creates a file names goodstuff.tar from the directory
and all files below the directory.
Now, if you move this to an Windows platform, you have to have a tar utility that works on that system. Archives tarred on UNIX systems will untar on Windows.
However, keep in mind that binary executables and similar files may not be compatible, so just because you can untar does not mean the files will run