After endless hours on various forums trying to find out the way to add graphics to the mac version i thought i'd add a "how to" for those that have been through the same trouble as me
First you need to get the graphics you want, I have downloaded all of mine from
www.sortitoutsi.net
You then need to download UnRarX from
www.unrarx.com for thos files that are in .rar format.
As in the Windows version, create a folder called "graphics" in the following path:
user/<name>/documents/Sports Interactive/Football Manager 2008
I found it is best to sub divide the folders into kits/skins/facepacks etc
You then need to add all files/rip the files using unRar if they are .rar files into the sub folders you have created.
Then go into the game preferences and in Display ans Sound untick "Skin Cache" and tick "Reload on Confirm"
This will apply the graphics you have loaded to the game.
You will not have to start a new game your previous saved game will have the graphics applied
Hope this has helped those who have struggled