A few good links about the above:

Virtual Box is Freeware and so is DOS Box

http://www.macwindows.com/emulator.html#WinonMac
http://www.makeuseof.com/tag/virtualbox-running-windows-on-a-mac-for-free-sort-of/
http://www.virtualbox.org/
http://www.virtualbox.org/wiki/Downloads
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http://www.freebyte.com/operatingsystems/
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http://www.codeweavers.com/products/cxmac/
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http://www.metacafe.com/watch/439071/run_mac_os_x_on_a_windows_pc/
http://pearpc.sourceforge.net/downloads.html
http://pearpc.sourceforge.net/doc.html
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http://www.apple.com/macosx/features/bootcamp.html
http://www.soft32.com/download_200398.html
http://www.versiontracker.com/dyn/moreinfo/macosx/29549
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http://www.dosbox.com/

http://www.dosbox.com/download.php?main=1

http://sourceforge.net/project/downloading.php?groupname=dosbox&filename=DOSBox0.72-win32-installer.exe&use_mirror=softlayer