CSV Enrolls & Groups plugin
The CSV Enrolls & Groups plugin allows you to import user enrollments for a course from an uploaded delimited text file. It is contributed by Fred Woolard.
Enrollments are made with the manual enrol plugin and using a selectable role. The plugin can optionally create course groups and assign the new enrollees to those groups.
Each of the users listed in the input file must have an existing Moodle user account; new Moodle user accounts will not be created.
This plugin was originally (Moodle 1.9) a refactor of the mass_enroll course admin mod done by Patrick Pollet and Valery Fremaux, using the standard groups course import plugin as a template. The current Moodle 2.x revision is again a refactor, but as a local plugin (placed into the local/ directory off the Moodle root), and accessed from the course administration menu under the 'Users' node.
Besides being able to create groups, you can select from existing groups and override the data file's group designation.