You might want to start by taking a look at the Supplementary Pages for this week...
... and you will also find many other resources online:
W. Schipper has put the complete Latin text of De rerum naturis online.
There is a very useful article in The New Schaff-Herzog Encyclopedia of Religious Knowledge, by Philip Schaff.
Curious about the other events taking place during Hrabanus's lifetime? Visit the 8th Century Medieval Timeline.
Hrabanus Maurus was also the author of religious hymns; the Latin text of his Veni creator spiritus is online at the Bibliotheca Augustana (this hymn forms the first movement of Mahler's Symphony #8); you will find two other poems by Hrabanus Maurus online at the Ad Fontes Library.
David Lancy's website on the Origins of Writing contains useful information and illustrations.
To learn more about the Latin liturgical tradition in the Catholic Church, you can look a Latin-English parallel Mass online and the Liturgy Archive also contains parallel Latin-English Mass. There is also an extensive Latin liturgical site which has significant portions of the Missale Romanum online.
There is an English-language site for "Hours" which allows you to follow the Lauds (or Matins) and Vespers daily, together with other liturgical offices. A growing online Latin Breviary is also available.
There is a parallel Latin-Old English translation of the Psalms (the "Paris Psalter") available online, based on what was probably a Roman Psalter with some readings taken from the Gallican Psalter.
