Ok, listen up. Netkas finally cracked the drivers for Radeon HD 2600 PRO, device id 9589.
For the moment it works only with DVI2VGA adaptor.
Here is the pack with the files you need to make it work.
You need 10.4.10 with kernel 8.10.3.
Put kexts in /System/Library/Extensions. Repair permissions.
Copy OpenGL.Framework in your /System/Library/Frameworks
Use kernel in the archive.