To run the Spore Creature Creator Demoo in Tiger, just edit the Info.plist file you'll find inside the demo application. Control-click on Spore Creature Creator.app, choose Show Package Contents from the pop-up menu, and open the Contents folder.
With Info.plist open in your favorite text editor, locate these strings:
<key>MinimumSystemVersion</key>
<string>10.5.3</string>
Edit the strings as follows:
<key>MinimumSystemVersion</key>
<string>10.4.11</string>
Save the changes and quit the editor. The demo works great on a first generation 3GHz Mac Pro with an ATI X1900XT video card.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20080622112907382