TinySID is a very small SID player. Current features include 99% 6510 CPU emulation and fat 6581 SID emulation including filters (which sound different to other players). It has nothing to do with other projects such as SIDPlay, and the 6510/6581 emulation is based on routines by Tammo Hinrichs that have been further developed.
SIDPlayer is a replayer program for C64 music (SID tunes), running under BeOS and Unix. You can think of it as being a stripped-down C64 emulator that only emulates the CPU and the sound chip of the C64. SIDPlayer can be used as a stand-alone player or, under BeOS, as a plug-in for CL-Amp and SoundPlay.
JMCE a multiple computer emulator, a simulator for 8-bit microprocessors (Intel 8080, Zilog Z80, Intel 8051, etc.) and for many of the computers based over them, such as ZX Spectrum, Altair 8800, and Z80Pack, running their original ROM and operating system. All JMCE computers can be configured programmatically or using XML. For example, it is possible connect the console of a simulated IMSAI 8080 to one TCP server or to one physical serial interface without writing even one line of code. It is also possible to change the memory for the Z80Pack computer from plain to banked memory only by editing a single XML file.