Registration in 2011 International Conference on Computational Science and its Applications, ICCSA'2011 is compulsory for at least one of the authors of the accepted papers. The registration is not available yet but it will be opened at due time. You should check at the main web page of ICCSA'2011, press the link "Registration" and follow the instructions indicated there.
Note also that the registration for the workshop is actually the registration for the whole ICCSA'2011 conference. Therefore, you will have free access to all the workshops and activities related to this general conference.
Finally, note that the workshop chairs are only responsible
for the academic aspects of the papers (including the submission,
reviewing and final selection, among others). For questions about
registration, lodging, visa, flights, or any other question, please