Welcome to the ATI Radeon HD Installer thread !
The installers can be found Here

Update: May 16 2009

ATI Radeon HD 4800 series almost all cards works

for more info please visit http://www.netkas.org

More installers are coming

Here are installers for 10.5.x
Here

Thanks goes to Netkas,Asap18,Paranoid,CycloneFr,Fleebaily33,XyZ,BlackKnight and the infinite amount of testers

FAQ

Mobility does not work due to different connectors (I REPEAT MOBILITY DOES NOT WORK YET)


ATI Radeon HD Cards Supported
For natit.kext please you Download

ATI Radeon HD 2400 to 3870
Download

ATI Radeon HD 3870x2 - CycloneFr made pkg
Device ID: 950F
Download

HD radeon users, instead of editing ATIRadeonX2000.kext if your card's ID is not in vanilla kext, you can use this Legacy kext and keep vanilla kexts clean. (If your card doesn't need a Bin patch to work also...)
Works fine with a HD2600 pro (ID 9589) on 10.5.5, 10.5.6 and 10.5.7 in /Extra/Extension
Add your ID in the plist if it's not already there


Click to view attachment

Hi,

I must say I'm slightly confused...

I have a HD 4550, I've opened the .plist and my device ID is there (0x9540) however what confuses me is this: Does this actually mean that upon installing this kext and applying all the appropriate permissions etc... The card will be identified with all of its features (changeable resolution, CI, QE etc...)?

Or is it a trial and error kind of thing and if it works it works, if not it doesn't?

Or is there another kext that needs to be installed for it to work?

And finally last question is this limited only to 10.5.7? Has anyone tried it with Snow Leopard yet?

Sorry for all the questions... and If anyone actually responds then thank you in advance!