Amazon is on a recruiting spree, which is wonderful thing. Right now I'm only doing a handful of phone screens and interviews a week, but my boss is doing probably two or three times that. Recently he went on a recruiting trip to Texas - came back with one hire.
We have a pretty nice 'pipeline' for recruiting, but there is a lot of competition for incoming resumes. We've gotten in the habit of checking the page that lists the recent candidates two or three times an hour - a new resume doesn't last for more than an hour or two before being tagged by other groups. After two groups tag the person, they are out of the pipeline, so we have to be quick.
The 'bar' at Amazon is pretty high which is both good and bad. We've been self-educating ourselves on interview skills. As many people are seasoned engineers, they've been through phases of hiring at other companies and are somewhat familiar with the process and what to look for. There are also some good resources for engineer-types - like The Guerrilla Guide to Interviewing. This is a good guide to the kind of hiring Amazon is doing.