I'm taking a course on database and need to build a model for a database. I would like to use Chen's ER model because that's what we were taught, but I'm having trouble in finding software that does that effectively. Where can I find it? Can I do it with Visio (are there any extra set of shapes)? Is there good freeware to get the work done? Is there any other product you would recommend as better?
It seems such a simple task, don't know why it's so hard to find a tool to build a Chen model.

here's a big list, hopefully one of them will have what you want...
Data Modelling Tools