Can I grant users permissions to create their own accounts?

Yes, as of SourceForge 4.1 SP3, it is possible to configure SourceForge such that new users can create their own accounts, but the accounts are not activated until a Site Admin approves them.

To enable this mode of operation, simply add the following line to /usr/local/sourceforge/sourceforge_home/etc/sourceforge_configuration.properties: sf.approveNewUserAccounts=true. Once this line has been added to the file, restart SourceForge for it to take effect.

The Site Admin can still create accounts for new users and they will not be held for approval. Also note that the user will receive an email from SourceForge telling them to confirm their password by clicking on the given link, and the link will not work. The password is properly set on account approval.