So, the newest graphics line from AMD ATI will be known collectively as Radeon HD 4800 and will contain more precisely two major cards: Radeon HD 4850 and Radeon HD 4870. It is even clear that the first one will be sold around 200$ (so notably under 200€) and the second around 300$.
AMD announced, in the recent presentation at Computex, that there will be quite a number of improvements in these cards to support nearly cinematographic quality in games, named Cinema 2.0. This was a surprise and it means that AMD is going to hit as hard as possible on nVidia.
The other muddy issue is the exact date of the launch. It was initially expected in May 2008. But it has been delayed (obviously) apparently for technical problems had to be solved in the last minute. AMD will not be able to hit the streets before nVidia can launch the GTX200 line (on June 17th), but it should arrive only a few days later. Some people say June 23rd (just enough time for the news people to move from one place to another), and it is now possible that both cards will arrive at the same time (initially the high-end Radeon HD 4870 was expected only for September).