Each fall, Haverford College holds an "Economics Alumni Forum." In October, Jane Dokko (class of '98) and I (class of '82) discussed "Rising Income Inequality: Causes and Consequences." Jane and I loosely divided up the subject by having her focus more on U.S. experience with income inequality in recent decades, while I focused more on long-term historical patterns like the old Kuznets curve arguments, along with international and global patterns of inequality.
A press release summarizing the presentations is here. A video of the presentations, roughly an hour in length, is available here. My presentation starts about 32 minutes into the forum.
Added: Greg Mankiw has posted at his website a video presentation of a symposium of Harvard professors discussing inequality, including economists Larry Katz and Ed Glaeser. It's about 80 minutes long, available here.