Wine
From TheLinuxVault
Wine is a compatibility layer for Linux to run Microsoft Windows programs. It does not "emulate" a Windows system because both systems run on the same processors. It only needs to provide access to libraries that function similarly to Windows libraries.
Wine Homepage http://www.winehq.org/
Wine Applications Database http://appdb.winehq.org/
Adobe Photoshop CS2 in Wine: http://news.softpedia.com/news/Install-Photoshop-CS2-on-Your-Ubuntu-PC-77260.shtml

