Use pagination to display them. Base the pagination start and end on an index in your database table. For example, if you have one million users, make sure you have a database row that's dedicated to counting from 1 to 1,000,000. Then make sure that row is an index, or even better, a primary key. When you do selects based on a primary key they will be very fast.
Jon Emerson
http://www.jonemerson.net/