After a bit of work and a lot of help from Pat we've made some progress.
- The Open Journal System seems to be a usable journal management system (although far from optimal). To get it going one needs to rewrite most of the information pages and pre-prepared mails, but it's possible.
- The most suitable copyright agreement we could find is the Creative Common Attribution 3.0. The only restriction is "Whenever a work is copied or redistributed under a Creative Commons licence, credit must always be given to the creator.".
- We need a latex style file. Any suggestions on what needs to be included in the style file? Theorem-environments, paper size, font size, font, figures...
- Name of the journal? Any suggestions? Journal on Computational Geometry (JoCG)? When the name has been decided we can easily get a domain name and an ISSN.