The download is working now!
extract it to c:\ and it will create c:\bridge\*.*
just click on the vmx to run
the default ISO is for STP, if this is not appropriate for your network then change the LiveCD to bridge.iso in the config.

Yes, absolutely

I just tested this to verify.
I have 1 box connected to the network with ethernet, and it has some linksys PCI card. I had used this b4 to test the bridge, but against an access point.

It's now connected to the general network, which has two sets of valid ip's, public and private. Machines with private ip's access the outside via an ISA server. I setup an adhoc network with my laptop, and another one. I set my laptop with the public ip, and the other with the private ip. The box running the bridge does not have the private ip on any interface. It actually has some 192. address on the wired interface, which is not on either of the laptops. You will have to set the upstream GW on the wireless cards.
ICS is not enabled anywhere.

Both laptops access the internet or the private network as if they were connected directly. I am not sure of any limit on the number of adhoc connections, but at least two are connected now.

In addition, a box with 2 wireless cards could run the bridge appliance, creating a range extender.

Is this appliance currently available for download anywhere?