How do I network the PowerBook G3 to another Mac?

There are several ways to network the PowerBook G3 to another Mac depending on the capabilities of the particular PowerBook G3.

Wirelessly (AirPort)

Two AirPort (802.11b) equipped PowerBook G3 models or one equipped PowerBook G3 and another AirPort or AirPort Extreme-equipped Mac, can be networked together without the AirPort hardware access point by using "direct computer-to-computer communications" within a range of approximately 50 meters. The PowerBook G3/400 (Firewire/Pismo) and G3/500 (Firewire/Pismo) support internal AirPort and other models can be configured via a variety of methods.

For Macs that have 10Base-T or 10/100Base-T or faster Ethernet installed and are capable of running MacOS 8.6 or higher, the first Mac can be added to an AirPort network via a crossover Ethernet cable between the computer and the hardware access point and the PowerBook G3 can be added to the same network by the wireless connection if AirPort is installed.

Wired (Ethernet)

If you're not interested in using wireless networking, or your PowerBook G3 does not have wireless capability installed, you generally can just use a simple crossover cable, or Ethernet cables and a hub, to connect another Mac to a PowerBook G3 or two PowerBook G3 models to each other.

Although it has not been updated in quite some time, Three Macs & A Printer covers basic types of wired networking in-depth.

Firewire

The PowerBook G3/400 (Firewire/Pismo) and G3/500 (Firewire/Pismo) can also be connected to another FireWire-equipped Mac, by using "FireWire Target Disk Mode". In this mode, the other computer simply will appear as a second hard drive on the desktop of the PowerBook. According to Apple "to use Target Disk Mode, simply connect the computers using a FireWire cable, then start the second computer while holding down the 'T' key on its keyboard."

For additional information, please refer to "How to Use Firewire Target Disk Mode".