Hello! Sorry for my poor English;)

"Unloading unneeded AGP modules..." works not correctly on my machine. Function "unloadagp" is included in /etc/init.d/xsession. In order to completely cleaning kernel from unneeded modules I need to run it several times.
It is conclusion from an experiment presented below:

$ lsmod|grep agp intel_agp 27420 0
amd64_agp 16772 0
sis_agp 12676 0
amd_k7_agp 12812 0
ali_agp 11136 0
via_agp 13952 1
agpgart 36044 7 intel_agp,amd64_agp,sis_agp,amd_k7_agp,ali_agp,drm ,via_agp

I copied "while" loop from "unloadagp" and executed it as root.

$ su
# while read m relax; do
> case "$m" in *_agp) rmmod "$m" >/dev/null 2>&1; ;; esac
> done </proc/modules
# lsmod|grep agp
amd64_agp 16772 0
amd_k7_agp 12812 0
via_agp 13952 1
agpgart 36044 4 amd64_agp,amd_k7_agp,drm,via_agp

# while read m relax; do case "$m" in *_agp) rmmod "$m" >/dev/null 2>&1; ;; esac; done </proc/modules
# lsmod|grep agp
amd_k7_agp 12812 0
via_agp 13952 1
agpgart 36044 3 amd_k7_agp,drm,via_agp

# while read m relax; do case "$m" in *_agp) rmmod "$m" >/dev/null 2>&1; ;; esac; done </proc/modules
# lsmod|grep agp
via_agp 13952 1
agpgart 36044 2 drm,via_agp

Now it's OK, there is only AGP drivers for my chipset. Next running loop does nothing.

# while read m relax; do case "$m" in *_agp) rmmod "$m" >/dev/null 2>&1; ;; esac; done </proc/modules
# lsmod|grep agp
via_agp 13952 1
agpgart 36044 2 drm,via_agp



# lspci
00:00.0 Host bridge: VIA Technologies, Inc. VT8377 [KT400/KT600 AGP] Host Bridge
00:01.0 PCI bridge: VIA Technologies, Inc. VT8235 PCI Bridge
00:06.0 Multimedia audio controller: Creative Labs SB Live! EMU10k1 (rev 0a)
00:06.1 Input device controller: Creative Labs SB Live! Game Port (rev 0a)
00:10.0 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 80)
00:10.1 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 80)
00:10.2 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 80)
00:10.3 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 82)
00:11.0 ISA bridge: VIA Technologies, Inc. VT8235 ISA Bridge
00:11.1 IDE interface: VIA Technologies, Inc. VT82C586A/B/VT82C686/A/B/VT823x/A/C PIPC Bus Master IDE (rev 06)
01:00.0 VGA compatible controller: ATI Technologies Inc Radeon RV250 If [Radeon 9000] (rev 01)
01:00.1 Display controller: ATI Technologies Inc Radeon RV250 [Radeon 9000] (Secondary) (rev 01)

# find /lib/modules/2.6.19/|grep agp
/lib/modules/2.6.19/kernel/drivers/char/agp
/lib/modules/2.6.19/kernel/drivers/char/agp/agpgart.ko
/lib/modules/2.6.19/kernel/drivers/char/agp/ali-agp.ko
/lib/modules/2.6.19/kernel/drivers/char/agp/amd-k7-agp.ko
/lib/modules/2.6.19/kernel/drivers/char/agp/amd64-agp.ko
/lib/modules/2.6.19/kernel/drivers/char/agp/ati-agp.ko
/lib/modules/2.6.19/kernel/drivers/char/agp/efficeon-agp.ko
/lib/modules/2.6.19/kernel/drivers/char/agp/intel-agp.ko
/lib/modules/2.6.19/kernel/drivers/char/agp/nvidia-agp.ko
/lib/modules/2.6.19/kernel/drivers/char/agp/sis-agp.ko
/lib/modules/2.6.19/kernel/drivers/char/agp/sworks-agp.ko
/lib/modules/2.6.19/kernel/drivers/char/agp/via-agp.ko


BTW, I discovered "pcimodules".