Attendance at U.S. university lecture halls is declining as more institutions offer lectures via the Internet for downloads to MP3 players.

Supporters say podcasts help students who miss a class or want to review the material, while professors "score points" for being flexible and being hip, the Chicago Tribune said.

At Drexel University in Philadelphia, a chemistry professor assigns podcasted lectures, recorded last semester, for homework, then uses class time to review problems. At the University of Michigan, lectures can be automatically delivered to dentistry students' computers or portable devices.

Taking it even further, at the University of Hawaii, hundreds of students in a computer science class are required to show up at a lecture hall only twice a semester -- for the mid-term and final exams.

Erica Carlson, a professor podcasting her lectures at Purdue University in West Lafayette, Ind., said the technology hasn't changed her two-hour lectures.

"We run the course just like we did before. Just now it is more accessible," she said.