They're not only informative, but also extremely entertaining. The official distributer of Microsoft language modules up through Office 2000 is ALKI software . You can find information at their site about what tools are available and their cost. If you have Outlook 98 you already have many spell-check dictionaries. The palette ranges from spelling and grammar check through a lexicon that can give definitions and translations.
Demos are available on-site.
Machina sapiens , a French Candian company, has the tool Correcteur 101. This company also has a Spanish proofing tool. A demo is available on-site. Pro-Lexis from Diagonal, in France. Unfortunately, I have no website address.