I did it with the firmware restoration util, flashed tomato 1.13 on an 500gP V2.

At first WLAN WEP/WPA did not work (like someone else wrote here), then I cleared nvram like it is said in the tomato FAQ. Now it is fine.

I'm very impressed with this, though I have yet to try other firmwares, I only had Asus standard fw on it.

The gui is very clean and compact, the router is very fast. I have Azureus running at full speed which was impossible with standard fw.

Thx
jim