I need to setup a Guest wi-fi SSID so customers/clients can connect to the internet, what's the best way to do that?

My company is looking into the same issue. Unless I read something better here, we are going with 2 Linksys wireless routers....running DDWRT.

We like to have the public AP auto-disabled during nonbusiness hours as well as blind to our network. It would be totally open, but may have a welcome portal via wifidog (which, thanks to serverfault, I have discovered runs nicely with DDWRT).

The staff router will not broadcast SSID and will use MAC address recognition, be available 24/7 and play nicely with our network.

I would strongly suggest putting guests on their own subnet with strictly controlled firewalls preventing anything but internet access.

Are you looking to do this through a single wireless router or through multiple access points? Many routers are multi-SSID as well as DMZ capable if that's what you want. I would look around for some higher end SOHO boxes like the one's from DrayTek. I have had good luck with them in the past. If you already have the LAN set up with a separate subnet for the guest network then you would just place an AP on each and name/secure them as desired. Both would do the job for you.

The new Apple AirPort Extremes support this.

"Now you can set up a separate Wi-Fi network with a separate password for your visitors. Simply enable the new guest networking feature, and your guests can use the Internet but can't access other parts of your private network, such as your computers, printers, and attached hard drives."

I have been using the guest network option on a new airport for about a month now and it has worked very well so far.