I have run Windows 98 in a version of Parallels ( version 3 i think) on Tiger 10.4.11.
With the Intel Macs, you can run windows in a virtual machine. Folks are cloning their old windows to a Parallels virtual machine.
Parallels:
http://www.parallels.com/en/products/desktop/
& some catalog order places sell Parallels for 9.99 when you buy a mac. You can runs versions of Parallels on Mac OS 10.4.
With VMware Fusion, run the most demanding Mac and Windows applications side-by-side at maximum speeds without rebooting
http://www.vmware.com/products/fusion/
Don't miss the free VirtualBox.
"VirtualBox is a general-purpose full virtualizer for x86 hardware. " Runs Windows on Mac OS.
http://www.virtualbox.org/
Robert