The following are links to various manuscript pages that can be found on the web. You are strongly encouraged to explore these sites and to send me (talarico@mail.csi.cuny.edu) any interesting new ones you find.
On my home page you will find other links (primarily related to the Arthurian Legend) to manuscript images.
Oxford University. Oxford is engaged in an enormous digitization project, making available on line many of its manuscripts and valuable paleographical information for researchers. One of the most famous call numbers is Digby 23, the Oxford Chanson de Roland. Browse the site and find many other treasures. The site also has links to other digitized manuscripts in other libraries.
Heidelberg University. One important manuscript that is available on-line is located at Heidelberg University. It is the German version of the Roman d'Eneas and is part of another large digitization project. The Introduction to the project describes its history and aims. The Roman d'Eneas is in the Palatine Collection (Cod. Pal. germ. 403: Heinrich von Veldeke) and is a German version of the 14th century manuscript B.N. fr. 60, which was edited by Aimé Petit for the Lettres Gothiques collection). Note: Only the Introductory page is in English. This site, like Oxford, has links to other manuscript sites on the web as well as an interesting site about manuscripts.
The Bibliothèque Nationale de France (http://gallica.bnf.fr): This is a starting point for many useful pages for illuminations of manuscripts. There is also the transcription (and a choice between Old and Modern French!) of Chrétien de Troyes's Lancelot ou le chevalier de la charrete (if you search under the alphpabetical list of texts available on-line). To browse the site and find other texts and manuscript illuminations, follow the link to Recherche and under the Liste de Documents, go to Manuscrits enluminés de la Bibliothèque Nationale de France.
At the BNF's Gallica site, you can also see BN f. fr. 60 (the manuscript of the Enéas that was edited by Aimé Petit in the Lettres Gothiques collection). This manuscript groups together the Roman de Thèbes, the Roman de Troie and the Enéas.
A very useful site, to learn about manuscripts in general, is the Medieval Manuscript Manual site.