A Box.net Business or Enterprise account allows you to create what are known as 'Sub Users'.  A 'Sub User' is a created username and password that provides visitors access to a specific folder within a user's account. Sub-User access allows colleagues to quickly exchange files within the security of Box.net without requiring them to register for an account. 

To create a 'Sub User': First, create or decide on a folder that you want your sub-user(s) to have access to. (Each sub user has access to one folder). Then, go to the 'Collaborators' tab, and select the 'Sub Users' sub-tab. Click the 'Add Sub User' button. Enter their username and password (you can always change the sub user password to maintain administrative control). Next, decide which type of account privileges you want the sub-user to have. “Read only” means they can only download files, “Write only” means they can only upload files, and “read/write” allows them to do both.

Now, choose the sub-user's "root" folder (the folder they'll be taken to upon logging in). If you choose 'MyBox' they'll have access to that folder and all of its sub-folders (i.e. your entire account). If you choose MyBox/CanadaProject, what appears as 'My Files' in their account when they log in is actually just the folder 'CanadaProject' in your Files tab. All files in your Files tab outside of this folder (and its associated sub-folders) will be invisible to them.

You can also manage your existing sub-users through this section. In the 'Sub Users' sub-tab, you can see the last time that each of your sub-users logged in as well as their most recent upload/download action. You can edit any of a sub-user's settings, except for their username, at any time.

Tip: It might be useful to create a folder for each of your sub-users. Then you can then transfer or copy all files you want that user working with into his or her designated folder for easy management.