For those of you who really love your classic Mac setup, you can run Mac OS 9 on an Intel Mac thanks to a program called Sheep Shaver by Gwenole Beauchesne. This isn't that new (Sheep Shaver has been around for a while, and the Intel transition's been covered a lot), but for those of you who need a tutorial, here are the steps:

Get Sheep Shaver

• Download Sheep Shaver. It is an open source PowerPC MacOS run-time environment that enables you to run PowerPC Classic MacOS software on your computer even if you are using a different operating system.
• Unzip it to a folder.

Get a ROM

• Download a ROM because Sheep Shaver needs it to work. You have two choices:
• You can use the ROM found at RapidShare; it's ready for use with Sheep Shaver.
• Apple has one their website, but you'd need a MacOS 9 to access it and you'd need an application called TomeViewer to extract your own ROM from it.
• Place the ROM in the Sheep Shaver folder.

Sheep Shaver GUI Part 1

• In the GUI you'll see many tabs. Click on the "Memory/Misc" tab.
• When you're in "Memory/Misc," click the "Browse" button.
• In the menu that appears, find the MAC OS ROM file in the Sheep Shaver folder.
• Still in the "Memory/Misc" tab, find the "MacOS RAM Size (MB)" field. Type in "128" to increase the RAM size to 128 MB.

Sheep Shaver GUI Part 2

• Click on the "Volumes" tab.
• Once you're in "Volumes," click on "Create." This will create a MacOS 9 volume to store your files.
• Save this new volume to your Sheep Shaver folder; make the image size at least 200 MB.

Finally, Install Your OS

• Place your MacOS 8 or MacOS 9 CD into your Intel Mac's drive. Press the "Start" button.
• Note: If you don't have a CD, Apple's vintage OSs are available for download at their Older System site.
• Sheep Shaver will launch and begin the install process and you're done.

Of course, performance may vary depending on your system.

And here's a bit more about Sheep Shaver from its documentation:

• SheepShaver runs MacOS 7.5.2 thru MacOS 9.0.4
• PowerPC G4 emulation on non-PowerPC platforms, direct execution otherwise
• Basic but portable JIT engine (x86, x86_64, mips)
• Copy and paste of text between MacOS and the host OS
• File exchange with the host OS via a Unix icon on the Mac desktop
• Color video display with support for run-time resolution switching
• Run-time depth switching from 1 bpp to current host depth settings
• Native QuickDraw 2D acceleration for BitBlt and FillRect operations
• CD-quality stereo sound output
• Networking: SheepShaver supports Internet and LAN networking via Ethernet and PPP with all Open Transport compatible MacOS applications

Download: [Sheep Shaver]