Before subscribing to any of the mailing lists, please make sure you have read and understand the guidelines.
While the mailing lists are not archived on Apache they are available at other sites, for example http://marc.theaimsgroup.com is pretty good.
Note that WSIF related mail was exchanged on the Axis user and dev lists until early 2003 (WSIF related mails had subject lines prefixed with [wsif]). So you can search those lists (also available on http://marc.theaimsgroup.com) for old messages.
The WSIF User List
This list is for developers that are using WSIF in their own projects to ask questions, share knowledge, and discuss issues related to using WSIF.(Medium Traffic)
The WSIF Developer List
This is the list where participating developers of the WSIF project meet and discuss issues, code changes/additions, etc. (Medium Traffic)