RadeonHD.org contains IRC chat logs for the #radeon and #radeonhd channels at FreeNode. More features are coming soon at RadeonHD.org. This web-site was established on November 19, 2007 and is currently considered beta. The IRC logging mechanism written is considered a work in progress, but expect more features in the near future.
The RadeonHD (xf86-video-radeonhd) driver is designed for the ATI "R500" Radeon X1000 series and newer graphics processors. The driver is open-source and written by Novell with specifications provided to the public by AMD. Currently this support does extend to the "R600" Radeon HD 2000/3800 series. While the driver supports RandR 1.2 and other basic functionality, it is very much a work in progress. The RadeonHD driver was publicly announced in September of 2007.
For more information on the current status of the RadeonHD driver, check out the Phoronix coverage.
The open-source Radeon driver supports earlier ATI graphics processors including the R100, R200, R300, and R400 series. There is also initial work for the R500 and R600 series support.