The Proofing tools (Speller [1], Hyphenator [2], Thesaurus [3]) for MS Office 2008 Mac are provided on CD-ROM.
You can find more information here [4].
Links:
[1] http://www.neurolingo.gr/en/technology/application_tools/speller.jsp
[2] http://www.neurolingo.gr/en/technology/application_tools/hyphenator.jsp
[3] http://www.neurolingo.gr/en/technology/lexica/thesaurus.jsp
[4] http://www.neurolingo.gr/en/products/proofing_tools/mso08.jsp