You will need the following:

• Nintendo GameCube Console
• Nintendo GameCube Memory Card (40 blocks free)
• Network Compatible Game (see our Online Game List)
• For Dialup:
  • Dialup Modem
  • Standard Telephone Cable
  • Analogue Converter (If you have an ISDN Connection)
• For Broadband:
  • Broadband Adaptor
  • Standard Ethernet Cable
  • Router or ICS setup (Recommended, but not required)

Nintendo Network Adapters connect to Serial Port 1 on the base of the GameCube console. Please see the User Manual for help with physically installing your GameCube Modem or Broadband Adapter. If you purchased an adapter used, you can download either manual here in PDF Format:

Dialup Modem Manual
Broadband Adapter Manual

A 12 digit MAC Address is labeled on the Broadband Adapter if your ISP requires this information.

GameCube Network adapters can be used on consoles of any region. Which means a Japanese Broadband Adapter will work on North American console and vice versa.

Homeland

Homeland uses a Nintendo Network Configuration tool. If Homeland is booted from a US console, all of the options for this tool will appear in english. I am guessing this tool is part of the firmware, but I don't have discernable proof at this time.

The main menu of Homeland displays the following:

はじめから　あそぶ (New game)
ネットワーク (Network)
せいさくスタッフ (View staff credits)

After you select network there will be 2 options:

ネットせってい (Network settings)
せつぞくテスト (Network test)

Phantasy Star Online

PSO uses Sega's own network configuration tool, which can be found under Options > Network Option.

LAN Games (Mario Kart, 1080, Kirby)

Each LAN game for the gamecube does not have a network configuration option. They all automatically obtain an IP address from your Local Area Network.

Creating a Local Area Network (LAN) is important if you want to expand your range of options for online play. This will allow you to have multiple network devices connected to the Internet at the same time, add additional network security, as well as allow you to tunnel LAN games for online play. Setting up either of the below options is required for tunneling games over XLink, GIT, and other third party tunneling applications.

Routers

We recommend routers by LinkSys. In our experience, they are more compatible with online console gaming than other router brands. The LINKSYS BEFSR41 is the cheapest 4 port router available as of this writing. Routers have better port forwarding options than ICS. So if you plan to host a lot of online sessions, its recommended that you purchase a router.

Internet Connection Sharing

If you do not wish to purchase a router, you can setup ICS (Internet Connection Sharing). You will need a computer with 2 network cards installed. Also, you will need a specific cable connection way to connect the Dreamcast to the PC. You have 2 options, and which one you choose will depend on what hardware you currently have available.

• Crossover Cable: A cross over cable is just like an Ethernet cable, however the CTS (clear to send) and RTS (ready to send) lines are crossed over. This is the cheapest solution, if you order a crossover cable online. Buying it from an electronics store often costs double.
  
  
• Network HUB + 2 Ethernet Cables: Connect the PC to the slot on the far right (usually slot 4), while connecting the Dreamcast to one of the remaining slots. Next you will need to toggle a switch from Normal to Uplink. This is essentially the same setup as a cross over cable.
  
  
• Windows XP is the recommended operating system for setting up ICS.

Click Here for a step by step process on setting your PC up for Internet Connection Sharing.

Phantasy Star Online for the Nintendo GameCube is compatible with America Online's Broadband service.

Phantasy Star Online for the Nintendo GameCube is not compatible with dialup internet services from America Online and Compuserve.

It is possible to use a Free Dialup ISP. Some work is involved to find a working ISP. This method is not recommended to get online regularly, since many Free ISP's accounts have poor connections or get dropped after a few months. However, for many people this is their only option. You should not base the success/failure of taking your GameCube online for the first time when using a Free ISP, because some ISP's restrict internet access to just web surfing. You might be doing everything correct when configuring your GameCube, but the Free ISP may be incompatible.

Nintendo.com has this to say on compatibility issues with Free ISP's:

"This is not an issue of modem compatibility. Many internet service providers require game developers to use proprietary development tools so that online games will work with that provider. If Nintendo and its third party publishers do not have access to these proprietary development tools, Nintendo GameCube games will not work with these internet service providers. Please check with your service provider to determine whether your service is compatible with Nintendo GameCube online games."

If you have broadband internet, you could have free monthly hours that come with your DSL/Cable package. Check your Broadband ISP's website, or call the customer support line to see if you have free dialup with your broadband internet service. Earthlink offers a limited amount of free dialup hours per month, and SBC offers unlimited dialup access with their DSL service.

The best option for dialup is to pay a monthly fee for a dialup ISP. You can find cheap ISP's that range from 5.95-9.95 a month.