University of California, Berkeley has provided a free online class on Basic Concepts of Operating Systems & System Programming (CS162) by Anthony D. Joseph.
The purpose of this course is to teach the design of operating systems and other systems. Topics covered include concepts of operating systems, networking, database systems and systems programming, including multiple-program systems (processes, interprocess communication, and synchronization), memory allocation (segmentation, paging), resource allocation and scheduling, file systems, basic networking (packet switching, file control, reliability), basic databases (transaction, SQL) security, and privacy.
You can watch the free lectures from the comfort of your home through your computer or phone or tablet though YouTube or iTunes.
To access the course via iTunes, click here.