Dec 31, 2005 11:13 AM|RogerSelwyn|LINK
I used a tool called MZNS.UserImport.
Essentially you have to extract your 2.x data into an Access database, which should be relatively easy. Make sure you have the passwords in clear format before extracting.
Then re-create roles in 3.x installation. Copy access database to website, and use module to create users/passwords based on queries from your access database.
Bear in mind in 2.x passwords are not case sensitive, whilst in 3.x they are.
Hope this helps