Contiki is an open source operating system for memory-constrained networked embedded systems. Version 2.0 of Contiki has just been released. The 2.0 release is the first release from the 2.x series, which brings many new features: dynamic run-time loading and linking of standard ELF object code files; Rime, a protocol stack designed for low-power radio communication; Cooja, a Java-based network simulator for Contiki; and an updated build system that makes cross-compiling for many platforms easy. See the Contiki website for details and downloads.
such a cool little OS. keep up the good work