... and their online store, bcfdirect.com HOWEVER, be warned that BD does not give cash refunds for returns, they grant store credit only. This means BRING YOUR STROLLER TO THE STORE (probably a good idea anyway.)
The Graco cover is the most widely available, but be advised that many strollers do not work well with it, especially the super-umbrellas such as Plikos, Chiccos and Maclarens. Because of the height of the hoods on my super-umbrellas, I ended up buying a cover for a tandem so that it would cover DS' legs and the cargo basket. It's loose on the sides, but is otherwise perfect. (BTW: these covers do not have frames like European raincovers; they suspend from the stroller hood.)