Ogg
OGG is an open source project for audio compression. Technically, OGG is a container format for files which contain audio compressed by one of a number of codecs. The OGG project also produces two codecs that would be relevant for the OLPC project, Vorbis for general audio files and Speex for voice files. Less relevant are FLAC (high quality lossless audio) and Theora (video)
In particular, the ability to record OGG/Speex files would allow the OLPC to be used for taking voice notes of classroom sessions. These can be used in two ways. One is for the student to review again at home if they have had difficulty in understanding it all the first time. The second is to send these files to students who were unable to participate in the classroom. These may be students who are ill or they may be students who live too far from the class to travel there daily. In such situations there are generally adults who are able to travel back and forth on a daily basis using some means of transportation (animal-drawn cart, bicycle, scooter).
Speex recording would also allow students to create their own audiobooks ala Librivox. Speex would also be an ideal vocal track for stop motion Animation.
The OLPC project needs to leverage these travelers, following the example of the Motoman project, to distribute content more widely and OGG recording capability will help in that effort.
More technical info on is available at Wikipedia [[1]]