Too many messages in the thread so I shall extract useful informations here.

Q: Don't work!
A: Please be more specific. What do you do and configuration.

Q: I install AGPGart and repair permissions but it doesn't loaded.
A: May be your chipset is not supported. Upload your ioreg (see topic).

Q: Double loaded or kernel panic.
A: It may be a problem with IOPCIFamily.kext. See topic.

Q: Loaded fine but after loginwindows.app I see black screen with live mouse.
A: Default AGP_Base value in AGPGart.kext/info.plist is not good for you. You need to edit it
QUOTE
sudo -s
password: -- enter your password
nano /S*/L*/E*/AGPGart.kext/C*/info.plist

Probably good values
<key>AGP_Base</key>
<integer>0xf0000000</integer>
and also
0
0x08000000
0x10000000
0xd8000000
0xe8000000
0xf8000000
For version 270 we found AGP_Base=aperture_size. Or Video_RAM_size

Q: I have software QE/CI
A:
1. Look GA.plugin/info.plist. You must edit it to
CODE
    <key>Personality</key>
    <dict>
        <key>IOProviderClass</key>
        <string>IOFramebuffer</string>
    </dict>

2. Aperture size must be 64Mb or 128Mb. Else - software QE only!

Q: I have blue screen
A: It is a problem of Framebuffer. You must to change IONDRVSupport.kext to version 1.4.3.
Take it here
If you use Callisto - uninstall it. It doesn't work in AGP mode.

Q: What version of AGPGart is best for me?
A: 265f, 267, 271 - choose one by own experience. All other versions have no sense.

Q: I have SIS, S3, VIA graphics card AGP.
A: Without graphics driver AGPGart has no sense.

Q: I have IntelGMA9xx graphics.
A: It is not AGP.

Q: I have nVidia. In system.log I see
CODE
NVChannel(GL): Graphics channel exception!

A: I have no answer. Look http://forum.insanelymac.com/index.php?showtopic=86054

Q: I can enter GUI but OpenGL crashes.
A: I saw the same crashes even without AGPGart. It is another task.