It’s been out awhile now, but if you haven’t seen it yet, take a look at Mike and Matt’s Introduction to Bedside Ultrasound. The ultrasound pocast guys have released this excellent overview of point of care ultrasound through the iTunes Store. This is certainly convenient as most of us have 3-12 iDevices on our person at any one time. Caveats are that this means that it is available only on an iPad using iBooks 2 or later, and ios 5 or later. Right now it is $29.99.
There is a lot of good content, but I think the best chapter in the book, is probably the RUSH chapter. :)