Today, I released uploadprogress 0.9.2, nothing groundbreaking since the initial 0.3 release, mainly bugfixes ( changelog). This means that there are still no other SAPIs than mod_php officially supported.
The main new function since 0.9.1 is uploadprogress_get_contents($id), which allows you to analyse the content of an uploading file during the upload and do appropriate measure (for example warn the user, that he doesn't upload a supported video format). You have to enable this feature in php.ini to make it work. This feature was provided by Ben Ramsey, so you have to poke him, if something's wrong with it.
As an alternative to the uploadprogress extension I can also recommend the YUI Uploader component, which uses Flash and therefore doesn't need any server side components for doing a progress bar. It also has additional features like multiple file selection. But a Flash based solution may or may not be ok for you :)
In a next post I'll write about some of the common pitfalls and problems one may encounter with this extensions. I hope that will clarify some of the more common issues.