I had a quick look at UBB users ,and I quickly converted all my 834 users to the WWWThreads format :
UBB uses a single file with *.cgi extension to store data each field separated by '|'
so you can 'cat *.cgi >>oldusers,
create a 'oldusers' table on your db with 12 fields then using 'mysqlimport' you can import oldusers in the new table You created
the ubb scheme is like this more or less :
username | pwd (in clear !!!!) | email | url | unknown | occupation | location | unknown (posts ?) | membership | quote | (email address viewable ?) | signature
so you can with a little sql skill import the important fields to WWWThreads.Users table
It worked for me
maybe I'll post something about importing posts when I'll have a look at that.
Excuse my poor English
