In July 2010 I visited the islands of São Tomé and Príncipe as the first week of the Tropical Birding tour of São Tomé, Príncipe and Gabon. See http://www.tropicalbirding.com for details of their birding tours.
The islands were a most interesting departure from the feel of the usual African destinations, indeed they did not feel like Africa at all. The highlight of this short tour was the two days camping in the mountains near Cao Grande where we managed to see some incredible birds endemic to this upland rain forest. We indulged ourselves on Príncipe with a one night stay in the tropical paradise retreat of the Bom Bom Resort.