Nisus Writer Express 3.0.1 and Pro 1.0.2 are out of beta and officially available.
These releases, which are free to current Pro and Express 3 users, are now compatible with Leopard (Mac OS X 10.5). There are also bug fixes, an Italian localization, and in the case of Pro, a few new macro commands. Release notes are available for Pro and Express.
Happy word processing!