I don't know why it isn't working for you guys.
(Though, I am using my onboard Intel Marvel Yukon 88E8056 Gigabit Ethernet port, working flawlessly using vanilla kext.)
In fact, the most pathetic thing is that I am using a dummy model "Made in China" RTl 8139 PCI Ethernet card!
But the attached kext does the job for me.
Try installing it as suggested above by "GoodWorld".
It does work. Probably, place the modified IONetworkingFamily.kext in /Extra/Extensions/
Then rebuild kextcache using the following command:
chown -Rf 0:0 /Volumes/Snow/System/Library/Extensions
chown -Rf 0:0 /Volumes/Snow/Extra
chown -Rf root:wheel /Volumes/Snow/System/Library/Extensions
chown -Rf root:wheel /Volumes/Snow/Extra
chmod -Rf 755 /Volumes/Snow/System/Library/Extensions
chmod -Rf 755 /Volumes/Snow/Extra
chown -Rf root:wheel /Volumes/Snow/System/Library/Extensions/
chmod -Rf 755 /Volumes/Snow/System/Library/Extensions/
kextcache -v 1 -a i386 -a x86_64 -m /Volumes/Snow/System/Library/Caches/com.apple.kext.caches/Startup/Extensions.mkext /Volumes/Snow/System/Library/Extensions/
chown -R root:wheel /Volumes/Snow/Extra/Extensions/
chmod -R 755 /Volumes/Snow/Extra/Extensions/
kextcache -v 1 -a i386 -a x86_64 -m /Volumes/Snow/Extra/Extensions.mkext /Volumes/Snow/Extra/Extensions/
Be it 32 bit or 64 bit mode of booting into Snow Leopard, the .mkext WILL
definitely work! Coz I keep switching back and forth between both the modes whenever I am trying new stuff like applications or Kexts.
Both are RAR files. Happy "connectivity"...