Malte,
There are two sets of workshops. The .LRN Users' Group Meeting is May 9th & 10th. The bulk of the presentations will be scheduled on the 9th and we will try to make sure that the sessions in English on 10th don't overlap with the second workshop below. We are still accepting presentation topics for the .LRN Users' Group Meeting. If you are interested, please let me know.
The other workshop is Foro hispano de .LRN y software libre educativo and will take place on May 10th & 11th. Deadline for paper submission was February 28th.
Hope that helps.