I haven't heard back yet. I'm not sure how well I did. I was able to get the programming questions almost totally correct. (In one example, I forgot to declare a variable; in the other, I left out a bracket. This would not have happened if I'd been typing the code into an editor. I just don't like writing code on whiteboards, especially while thinking about how the code is to be written.) I also was able to describe in detail how the ping program works (down to the level of how the ethernet packets are sent and received), although if I hadn't looked over my review notes before the interview I might not have explained how the ethernet addresses are obtained.
OTOH, I had some trouble with some questions. One that stands out was to explain the difference between big and little endian. I had actually reviewed this some time ago, but I was having trouble remembering this example, so I had to explain it in terms of network byte order, which isn't the simplest, clearest explanation. There were some other things I didn't do so well on that had to do with projects I'd worked on a long time ago.
I've sort of come to the conclusion that I don't really like interviewing. I just don't feel comfortable and perform worse than I would just having a conversation with a coworker. Also, while having worked on lots of different projects may help me in an actual job, because it gives me different perspectives, it seems to hurt me in interviews because it provides the interviewer with opportunities to stump me because I don't remember some things about the projects I worked on.
BTW, someone who (presumably) works at Google had a Q&A session about the company, interviews, projects, etc. He spends his 20% time on Google Calculator. He actually fixed a lot of the bugs that people had complained about earlier. He also pointed out that MSN Search is able to find roots of some polynomials. (I didn't realize it did this.) For example, try this. The answer's not quite correct. (Why do I remember why, but not about endianness? OTOH, I've forgotten other algebra stuff, especially linear algebra. Too bad, as it might help me get some jobs.)