The online coding interview is the pre-screening part of the journey, in which we should decide whether or not it makes sense to fly you out to an onsite interview or not. Obviously, we don't want to spend a lot of time and money on someone who doesn't stand a chance of at least meeting the bar, but we also don't want to go overboard in the initial screen, so there's a balance to be found in the complexity of programming questions which are asked in the online interviews.
Hence, unlike certain people who're trying to make a career out of consulting armies of young engineers who see meaning of life in getting a job in Silicon Valley (or die trying), let me tell you the distilled truth about the technical interviews for new grads:
It's nothing special, really.
See, you were either sitting on your ears in school, or you tried to make something out of it. You either loved your work and had genuine passion for computer science, or you tried to game the system so you can pass, somehow. In case of the former, you didn't restrict yourself to school materials - you read, and then you read some more, and then researched even more and coded the most. If you're that type of guy or girl, then these technical interviews will be no more difficult than what you had for homework, or exams.
Sure, brush up on things. Go through Cracking the Coding Interview if you must; by all means, revisit CLRS, but ultimately, these should be just subtle differences if you really have it in you. The knowledge that will be probed in the interviews should be deep in your head by now. Does that seem unreasonable?
If you do have the knowledge, than your psyche is your worst enemy, because your nerves may inhibit your reasoning. The best way to handle future stressful situations is envisioning them and playing them out in your head, over and over, until you grow accustomed to all those unpleasant sensations with which your body will react. This has been said and written so many times, it's almost a cliche, but - do mock interviews and practice writing code on whiteboards and talking to people while you do it, until you're comfortable with it. With online interviews, you might experience bad audio and you might not understand everything the interviewer says, especially if they have a heavy accent. Don't panic, ask questions, clarify and don't move until you understand what you're asked. You can prepare for that by practicing that with your friends, over the phone.
Focus on managing psychological part of the interview if you have the technical abilities. If you don't, well then good luck with that.
Yeah, and what those other guys said about those websites that help you prepare by showing you how to reverse a linked list.