There are two versions: Wi-Fi only and WiFi/3G. Both versions will ship on August 27th, and can be pre-ordered now. The Wi-Fi only will cost $139, and will come in Graphite. The 3G version will cost $189, and you can choose between white and Graphite.
Amazon has just announced the third generation of their popular Kindle e-reader devices. The new Amazon Kindle is smaller, and lighter but still has the same display size. They are using the new 'pearl' displays, which offer an improved contrast (by 50%!). The display size is still 6", 600x800.