Meg Cormack and others:
You may wish to consider the following:
The Auchinleck MS website, at http://www.nls.uk/auchinleck/ A snippet of Lydgate, at http://web.uvic.ca/hrd/lydgate/ (a pilot XML project at the University of Victoria) The EETS pilot project (part of the Ancrene Wisse), at http://www.tei-c.org/Projects/EETS/ The Charrette Project, at http://www.princeton.edu/~lancelot/ http://www.princeton.edu/%7Elancelot/ (if your students want something in French)
All provide MS images and transcriptions. The EETS Ancrene Wisse also provides a translation. Translations of some material from the Auchinleck MS are readily available in print.
There is a good on-line paleography course at http://www.medieval.unimelb.edu.au/ductus/
You may also wish to investigate some CD editions, e.g. Murray McGillivray's _Hypertext Book of the Duchess_ (University of Calgary Press) or Gerrit Bunt's _William of Palerne_ (SEENET).
Hope some of that is helpful. I would be interested to know of other similar sites.
Yin