MS-Word has inbuilt facility for this.For Office 2007 or higher, in English, directly refer to this link.
Since a number of my friends use Dutch version of Office 2003, the following can help.
- Open any one of the versions (A) of the document. Typically this would be the initial version, on top of which chagnes are made,
- Go to Tools menu and click on 'Compare & Merge Documents' ('Documenten Vergelijken en Samenvoegen' in Dutch- see picture below),
- In the upcoming dialog box, select the other version (B) of the document, click Ok;
- Another dialog box will open to ask in which version (A or B) we would want to see the changes marked. Choose as per your choice. By default it would be A.
- Click Ok. You would see all changes marked in the chosen document in track-change mode.