I am new to Microsoft (SharePoint technologies). I am trying
best way to implement SharePoint Portal 2003 and assign security.

This is what I am trying to do.

1. WE have a SharePoint portal 2001 deployed in our company
All folders are setup and security assigned to each folder.

2. We need to migrate 2001 folders and deploy SharePoint Portal 2003.

I know the data stores are different (2001 - Exchange) (2003 - SQL)
Has any one done this migration ? IF so is there a migration guide
available ?

3. Now I know SharePoint Portal has document libraries
Do these map to Folders in SharePoint Portal 2001 ?