go to www.sortitoutsi.net and find the premiership packs under the kit/badges/facepacks sections. They should come with instructions however i'll tell you anyway. You must have a unzipping program such as winrar. You then need to download the files and unzip them into the relevant folders. So for kits.... unzip to the kits folder which you'll find in the folder named 'graphics' which should be in the folder named 'data' which should be in the sports interactive folder in the my documents area. I'm pretty sure that's right, and i'm damn sure i could have xplained it better ;D
wouldnt know but i would imagine so... the game should start with all the data saved from the last game... all you are doing there is adding to the original data pack and not removing it.
No a new game is not required for the new graphics to take effect. Go to preferences, display & sound then untick "use skin cache" and then tick "always reload skin on confirm".