Hook up your PS2 to your computer and run homebrew software with ps2link software, crossover cable and a modchip or exploit code. This tutorial will be limited to the software needed on the computer and PlayStation 2 and the hardware to connect the two. I may cover installing a legal modchip in future instructables.
Step 1: Download Loader Software
You will need to download the ps2link (I downloaded v1.24 because it had an ISO that booted right off the CD)
and a PC side client for ps2link, if you are using windows, xlink is a good graphical interface.
You can obtain both easily here:http://ps2dev.org/ps2/Loaders
Step 2: Burn the ISO
Now that you have the package downloaded, you need to un-archive it. Then burn the ISO file to a CD, I used alcohol 120% but any CD/DVD burning package should allow you to "Burn Image" from a file.
Step 3: Connect Your PC to the PS2 Console
You will either need a crossover cable to connect your ethernet interface to the PS2's network interface or have both the console and computer hooked up to the same switch or hub with normal straight through ethernet cables.
In the photograph I have my laptop connected to the PS2 with a crossover cable.
Step 4: Start Your Software
Now you need to start up XLink and boot the CD in the PS2. Booting should be easy as restarting the PS2 with the CD in the drive and selecting "Boot Media" if you have a boot-manager installed.
If everything worked fine you should see the following screen on your television screen, and the XLink status light should read "Online" and turn green.
Step 5: Run Your Software!
Now is the fun part, you can run PS2 executables *.ELF files by using the "Run" option on XLink. There are some neat Demos on the ps2 dev site along with some homebrew games. I've had a hit/miss experience with the downloaded .ELF files. Check out some demos here:http://ps2dev.org/ps2/Demos
and sample code here:http://ps2dev.org/ps2/Code
setting up the compilers and toolchain for compiling your own ELF binaries will come soon!