George Foreman grill covers can be purchased from Appliance Factory Parts and KitchenCorner.us. Covers can also be found at Amazon and eBay, as of 2015.
Appliance Factory Parts features covers for George Foreman grill models GR59A, GR59ACAN and GR26BW. The website has live chat support from parts experts,and has an A+ rating from the Better Business Bureau.
KitchenCorner.us sells a cover for the George Foreman 15-serving indoor/outdoor grill. Covers ship free for all domestic orders, and come with a 30-day, money-back guarantee.
Amazon sells George Foreman grill covers for multiple models, and eBay has a number of auctions for new and used covers.