Great, it works! Thank you very much. Can you add a link to the page of the post for a normal permalink structure? Maybe you can add more features later for that, but I suppose the majority of the websites using WP or WPMU use the standard structure, don't they?
Another think that might be cool would be the possibility to have the blog name and the author name in different styles, since now it's all under the "title". (you can check http://abietto.net/testMU/ where I'm testing WPMU and some plugins to see what I mean).
I have another little problem that I'm sure it's nothing, but my php skills are really dumb. As you can see on the site, a title like "abietto's" is echoed like "abietto\'s". I tried putting a "stripslashes" command on the line in many ways, experimenting a bit, but I didn't find a way to take away the "\". How can this be done?
Thanks again, I think this plugin should be incorporated in the next releases of WPMU, since it gives much more sense to many websites and portals, collecting the latest news from all the sub-sites in a single page!