Similar question: http://stackoverflow.com/questions/2541502/looking-for-a-free-xsd-scheme-editor
Eclipse was mentioned in a similar post, but it is too heavy for my requirements.
I am willing to try out a wine option, but then I would need detailed instructions.
I am running Ubuntu 9.04 and upgrading is out of question, sorry.
EDIT: I want something like this for xsd under Linux.

The idea is - I should be able to tweak a .Xsd file without having to worry about changing the wrong part of it. For instance, where do I add minOccurs and maxOccurs? With a good editor, I would not have to ask such question.
The xsd files get pretty large, so editing them by hand is error-prone.