WSIF has it's own home at http://xml.apache.org/axis/wsif.
The first Apache WSIF release candidate is currently being worked on and should be available in the near future. Check back here and watch the mailing lists for news.
You can download interim releases from http://cvs.apache.org/dist/axis/wsif/.
Detailed list of changes in this release is available (you can also visit online list of changes in the latest CVS version to monitor WSIF progress).