I'm not an expert, but I have spent the last 5 years trying to help a friend get an H1B. He was able to get a student visa and earn his undergrand and master's engineering degrees in the U.S. But he graduated as the economy fell and couldn't get a job for the life of him. From what he's told me, it's near impossible unless you have an inside connection with someone at a very big company such as Intel. The cost is roughly 30-40k to get an H1B and the competition is so tough, you better have your PhD and a 4.0 GPA to be competitive.
One caveat is that a company has to show that they couldn't simply hire someone from the U.S. and that in order to get the skillset they need from someone, they needed to get it overseas. This is tough, especially for a startup.
Again, I'm not expert, but from close experience with a good friend (who is now stuck back in Venezula btw) it's tough as hell :(