Visa requirements...Kenya

Hello,
I'm travelling to Cameroon in a few months. I have a Cameroonian visa
but I have a layover in Nairobi, Kenya for 1 day. Do I need a Visa for
Kenya? I would not mind just staying in the airport all night. Is it
possible to stay in the Kenyan airport all night? Also, If I wanted to
go travel around Nairobi for a day would I have to get a single entry
visa or is it possible to get a transit visa. How do I get a transit
visa if this is needed? At the Kenyan embassy or upon arrival in
Kenya? Thanks.
Cschwa

Transit visas good for 3 days are available
on arrival at the airport. $20 US.
The Embassy web site doesn't indicate
if you need the 2 photos for this visa,
so be sure and have them with you,
just in case. 2 passport-sized photos.

Thanks for the quick replies. Peace.
Chris