As far as I can see nobody bothered to update anymore the topic so I thought to drop by and let everybody know that the Asus P5G41-M LE works just perfectly with Mac OS X Lion 10.7.2 (I did not tried to update yet to 10.7.3 but I am sure it will be just a security/bugs patch) and everything needed in first place worked like a charm.
For those of you looking for a DSDT.aml patch - I think you might not needed it as the motherboard is working just fine without even patching the BIOS with the SLIC version kindly provided in the beginning of this topic. I might give a try to that firmware, however I am stick to the trick - If it works just fine do not do anything that might brake it
In order to have the Fast 1GB Ethernet working all you have to do from the installation disc (I used iAtkos L2 - Lion 10.7.2) is to choose Atheros in the Wired Network Section and that is all. For my video I used a cheap Nvidia GT240 which is more than perfectly recognized without the need to select anything from the patches/drivers on the installation media.
I had one small problem though (I might still have it but I just installed VoodooHDA that is listed in the first post and did not reboot yet) and it was the sound even though I have selected the VoodooHDA from the installation media in Sound hardware. I will see in a minute after the reboot whether the sound would be working, however I am more than sure that it will.
As an alternative to my wired network I tried to use Belkin n300 mini USB wireless adapter, and it was not found from the beginning however I have found a pack that I can install and play with it. After the installation my usb dongle was recognized however I could not see the wireless networks listed and this is something I am working on right now.
Well good luck every one ad here are my specs in case somebody with similar ones is looking for a hint how to set up a fully operational Mac OS X Lion (the latest so far version):
Memory: 2GB DDR2 667
Video: Nvidia GeForce GT240 (the last I think that does not require high wattage power supply - the 6 pins connector - 25$ Ebay etc.)
Motherboard: Asus P5G41M-Le
Bios: Official preinstalled version
Hard drive: 160GB SATA Western Digital & 1TB Western Digital Black Caviar (as a storage)
Mouse: Chinese USB wireless for 5$ - working perfectly and only needing to inverse the scroller directions (not a big deal)
Keyboard: Gateway 102 keys
Screen: LG Flatron W1942TQ (perfectly recognized and set up to maximum resolution 1440x900 by the video card)
Sound speakers: irrelevant
The only thing that is not working so far and I shall see whether it will ever work on my dual boot pc is the USB Card Reader that was built in the box, however I am still keeping my old Win7 just in case of a need.
Well good luck everyone. If you need the DSDT.AML patch, I think there is one available for Asus P5G41-M LX that you can give it a try at least for the sound/network, however I would rather use the defaults if they are working fine. In order to find out whether the sound listed in the post of Crazy About Mac (Thank you very much MAN/Lady!!!) i shall reboot now. Stay tuned and be happy

Little update - the sound works Perfectly now and in order to "Fix" the newly introduced Mac OS X Lion thinking of Mouse scroller direction simply go to System Preferences > Mouse and remove the tick mark "Move content in the direction of finger moving..." (the first option in the newly opened mouse configuration dialog.
Searching in Internet I have found few websites offering to even install a software that can do the same job, however let's be reasonable and use the least additional tweaks if something is already built in the system.
I have noticed also that the Sleep problem still appear, however despite the fact that I will search some info about that topic, my computer is a desktop machine and I would rather just set in the power options that I want only the screen to turn off but never go to a sleep mode in case I cannot find a fix for that yet. So not to worry too much on that.
So far so good. I just checked in Hardware Info and every single piece except my card reader is recognized, and perfectly identified as well as the screen.