go to you invision board admin panel, go to your skin section then the export option, and export your skin.
the file will be saved to your achive out folder or there is a link to it on the page that tells you the file was exported make sure you delete the file that appears in the achive out

the file is a tar file (ipb 1x) or two files in ipb2 (a skin file and a img file) either why these then can be zipped up and sent out

the zip file should then be extracted by the user but dont extract the tar file or the two that were exported on ipb2 other wise the skin wont work.

then upload the files by either the achive in and the admin panel once again.
that should do it if youve got any questions post em or email me