Your report should contain the following:
A one- to two-page summary of Vorbis.
Technical details including, but not limited to, sample rate, bit rate, compression ratio, support of variable and constant bit rate, brief specification of Vorbis.
A comparison of Vorbis and MP3. You may search the Internet for any comparison reports of listening quality. Note that you should give the comparison of different bit rates.
A list of references
All relevant information you may find in xiph: http://xiph.org/ogg/