"libcpu" is an open source library that emulates several CPU architectures, allowing itself to be used as the CPU core for different kinds of emulator projects. It uses its own frontends for the different CPU types, and uses LLVM for the backend. libcpu is supposed to be able to do user mode and system emulation, and dynamic as well as static recompilation.
Getting Started: How to download & compile libcpu and how to try out the included demos
Public Interface: The interface that clients of libcpu link against
Design: The basic design
Clients: Information about clients currently using libcpu; this includes test/demo/regression tools.
Services: SVN, IRC, Mailing List, Bugtracker