My internet discovery of the day: The Internet Bird Collection. Videos and photos, worldwide, by category. They are up to 40,000 videos thus far.
Ed. note: This is a wonderful resource. I just perused their videos of the Parulidae (New World Warblers). Fantastic. Identifying many of the female warblers remains just as tough for me as ever, I am sorry to say. When they are flitting through the treetops, I am lucky to get a glimpse. For example, below, female Tennessee Warbler, via CLO: