Most of the information I am about to relay can be found here at the official walk through for setting up a Build Environment for the full Android system. I wrote up a short shell script to do all the set up work and start a full compilation of the system for the efficient that I have made available here, though I will point out it is necessary to read through it and make some small changes to customize it for your own folder naming conventions.
I found that I hit the least snags using the latest Ubuntu x86_64 version, so the script installs dependencies for that distro. Something else could be substituted in but all the Android testing is done on Ubuntu systems, and the build process will stop and complain if you try x86.
After the compilation finishes, all of the output binaries will exist under the "out/" subdirectory. Usage for the emulator is described on this website, although more options are available by querying the binary. The emulator can be built individually by running 'make emulator' in the main Development Environment folder or with more control by following the instructions in 'external/qemu/INSTALL'.
I chose to build the full Android environment so I could have more control over building an Android Kernel as well as having full access to all the necessary emulator bits.