Squid proxy on Windows

We’re impressed with Squid after playing around with it on our Test Network, but before making any major changes, I wanted to check that I’m on the right lines.

We currently have a Netgear DM111P ADSL modem hooked up to a Netgear FVS336G Firewall, which then goes to our Switch. Our SBS server is connected to the Switch.

If I install SquidNT on our SBS Server, and configure each client Web Browser to use the SBS as the Proxy will that work with our exisiting setup? Or should we remove the Netgear FVS336G and replace it with one of our redundant PCs which would run IPcop?

Thanks in advance for any help given.