MS Windows users frequently exchange documents generated by MS Office. Redhat now ships with Open Office, a suite with many of the features supported by MS Office. At the time of writing, the version of Open Office was 1.0.1; I hope the following cautions become obselete. While Open Office is capable of reading many MS Office documents, the exact formatting details are often slightly off, so that Powerpoint slides are formatted significantly incorrectly. It is generally dangerous to pass any mildly complex document back and forth between Linux and MS Windows users, editing it with both MS Office and Open Office.
A good supplement to Open Office is remotely using MS Office on a machine which is shared among many Linux users. In addition to commercial programs which provide this functionality (XXX name?), a free program called VNC is capable of exporting a MS Windows server's desktop to a Linux (or Windows or any machine that runs Java) client. XXX How does VNC interact with security? XXX example?
Alternately, a Linux user can adopt the strategy of dual booting; use Open Office on a day-to-day basis to read MS Office documents, and boot into MS Windows only when working on a document which is being modified by both MS Windows and Linux users.