The SP line is available solely in 120mm, the most commonly used fan size for radiators and heatsinks, while the AF series ships in 120mm and 140mm, with a 200mm version still in the works.
In a unique twist, each fan comes with three colored rings that can be swapped by the user. One of the rings is white, allowing modders to apply their own paint. Red and blue rings are included, as well, but no black... yet.
Newegg already has a number of the fans in stock. The going rate is $17 for 120-mm models and $20 for the 140s. There are discounts if you purchase more than one fan, and Corsair is even offering dual-fan packs that cost a few bucks less than a pair purchased separately. Expect these fans to start trickling into Corsair's other products over time.