"Think of Wine as a compatibility layer for running Windows programs. Wine does not require Microsoft Windows, as it is a completely free alternative implementation of the Windows API consisting of 100% non-Microsoft code, however Wine can optionally use native Windows DLLs if they are available. Wine provides both a development toolkit for porting Windows source code to Unix as well as a program loader, allowing many unmodified Windows programs to run on x86-based Unixes, including
Linux,
FreeBSD,
Mac OS X, and
Solaris." source
http://www.winehq.org/
Codeweaver CrossOver is an enhanced version.
http://www.codeweavers.com/products/cxoffice/
This German fellow has successfully run Google Sketchup on Linux.
http://aksels.de/software.php#sketch
Some have even run PalmOS emulators on Linux.
If all else fails... run xp.
