If, like me, you somehow managed to get a CS degree without taking a compiler course, this article on GCC (the popular Linux/Unix compiler) from Red Hat's newsletter is a good read. It's a high level description of how GCC works with some interesting bits about significant architecture improvements coming in GCC 4.0. I was quite impressed/shocked to read that GCC has over 2.1 million lines of code.

Now I just have to find a similar article about .NET and Mono's compilers.