The following message was posted to NV in a comment thread by Guido's sister in law. She has agreed to me giving it wider notice here.
FYI, Guido passed away in Nairobi last week. He was only 34 years old.
Here is a 5/6/08 facebook post from his sister Sandra:
I am sorry to have to inform all of you of Guido's sudden passing in Nairobi. We know he died at home between Friday night and Monday morning. We do not know the cause or time of death. However, no foul play is suspected. You'll all agree with me that he was an amazing human being who had so much to give the world and who was working to make the world a slightly better place. At this time, we have not made any funeral arrangements. My parents are planning to travel to Kenya to take care of many details.
If you have remembrances of Guido that you would like to share, please do so. I would like to create a tribute in his memory and share this with family and friends. You can reach me by e-mail at firstname.lastname@example.org. Thank you for being his friends and providing a support network for him.
His sister, Sandra
Guido will be sorely missed, and he has many friends from his time here on NV. Here is a quick biography he wrote for another site:
In his modesty he underplays his role as a leading advocate of Open Source in Africa. You can get a sense of that from this article of Claus's.