wds setup

I have read over a couple of threads about wds on airport express. I am curious about this setup and configuration. More on the setup. If I am reading this correct with wds you do not need a ethernet cable to have this work? If this is so will be a true repeater and a receptible is all you need? Last part, can this work with any router or does it have to be an airport?

Thanks

Cohen

No you do not need any physical connection to have your Airport express extend the wireless network.

According to Apple's FAQ - you need to use an Airport base station for the Airport Express to extend the WDS network.
AirPort Express frequently asked questions (FAQ)
Now do note it looks like the Airport Express can be the main WDS so in theory if one Airport Express is on your network you could use other Airport Expresses to extend from that Airport Express.
http://docs.info.apple.com/article.html?artnum=108038#2.5