Math 415.01: Ordinary and Partial Differential Equations
Syllabus (Updated 7/22/11 for Office Hours)
Calendar (Updated 6/22/11)
Carmen (Homework Assignments and Announcements)
Academic Earth: Video lectures on various topics, including Differential Equations.
WolframAlpha: An online calculator, useful for checking answers.
Let me know if there are other useful sites you know!