Willem Hoek on Jan 11, 2010
The SAP MM certification is based on about 4-5 weeks of SAP courses.
For more details of areas covered in exam, see https://training.sap.com/
Good luck with exam post to comments below any feedback regarding format.
Update 19 Oct 2010
I see booking for certification can now be done online (via 3rd party).
Certification can also be done at other centers – not just SAP itself.
From link above I was also able to get some sample question – about 10 or so.