You can just create an SQL file to upload into your MySQL database. It would look similar to this:
# --------------------------------------------------------
#
# Table structure for table 'table_name'
#
CREATE TABLE table_name (
user_id mediumint(8) NOT NULL auto_increment,
user_active tinyint(1) DEFAULT '1',
user_name varchar(25) NOT NULL,
user_pass varchar(32) NOT NULL,
PRIMARY KEY (user_id)
);
# -- User Info
INSERT INTO table_name (user_id, user_active, user_name, user_pass) VALUES ( '', '', 'admin', 'password');
INSERT INTO table_name (user_id, user_active, user_name, user_pass) VALUES ( '', '', 'user', 'password');
Then you save the file as filename.sql, and run it in your MySQL database. You'd have to create the INSERT INTO line 50 times, and change the user_name (for this particular insert) but it's easier than creating a form and entering the data for each one. I think, anyway.