iTunesU is a free facility based on iTunes.  You can record any length of video or audio and make it available for downloading into any MP3 capable player.

For short segments you can record using a web camera and upload into YouTube.  This has the advantage of being extremely easy to do and easy to view, however it is limited to a maximum of 15 minutes and 2 GB in size.

Although its primary use is for remote classrooms and teleconferencing,Adobe Connect also has a recording feature which can be used even if you are not connected up to remote sites.  This has the advantages of not having a time limit, AC also has the ability to allow you to switch between showing your lecture and showing your computer desktop.  The resulting files can be linked into your Learning Management System or simply emailed to your students.

You can also request the Multi-Media Systems group to record your lecture and make it available on a DVD using a traditional tripod-mounted video camera.