Don't take "NO" for an answer!!!
You can either "dual-boot" as the last poster suggests, or as he also suggests, be able to have concurrent access to your CD-ROM and Lion or Mt. Lion
Here is an example of the educational CD-ROM ("Teacher Express") requiring PowerPC running in Snow Leopard Server (with Rosetta) installed into Parallels 8 for use in Lion and Mountain Lion:
[click on image to enlarge]
Apple is now selling Snow Leopard Server for $19.99 + sales tax & shipping costs at 1.800.MYAPPLE (1.800.692.7753) - Apple Part Number: MC588Z/A (telephone orders only).
Parallels offers a 14 day free trial download of Parallels 8 at its website:
http://trial.parallels.com/index.php?lang=en&terr=us
Parallels 8 sells for $79 retail and can be found at a discounted price if one searches the Internet.