We have several Mac minis, all connected to our network with Ethernet. We just got a laptop, but we don’t have a wireless router. Can one of the minis create a wireless network?
Yes, that’s super-easy. In Tiger: On one of the minis, go to System Preferences > Sharing > Internet. In Leopard: System Preferences > Sharing, and turn on “Internet Sharing” in the list of services. In there you can share the Ethernet connection via Airport, which tells the mini to create what’s called an “ad-hoc” wireless network. You can name it what you want and password-protect it, too.