Hello Petro,
The MOUS tests are designed to demonstrate that a person has the necessary experience to accomplish tasks at either the Core or Expert level. Anyone can say that they know how to use Excel (when in fact all they can do is chew the gum

), but if they have a MOUS certification in Excel they have demonstrated knowledge about the program.
As an Instructor it confirms your knowledge level about the product and lends credibility to yourself.
The exams themselves are relatively straight forward.
read the instructions then do the task. Yes, you can use Help, however the Exams are timed and once you have moved to the next question you cannot go back.
I would check out
(it will direct you to the proper site in Microsoft land) and look at the objectives/criteria for each exam. Make sure you are comfortable with all the items to be tested. In addition check out all the links on the left side to other resources.
If you want to become a Master Instructor there are additional requirements that must be met. See
to view the requirements.
I've past my Office 2000 exams and I'm currently working on Office XP, and Project 2000. In addition I'm working on my Corel WordPerfect 9 and 10 Certification among others. As an Instructor I offer solutions in whatever product the client uses.
Good Luck,
Michael
Microsoft Office 2000 Master Instructor