6502
6502 Cross-Development Languages and Tools, Acorn Disassembler, Antic Software Archive, Commodore Programming Utilities, Dan's Atari 5200 Tech Page, dis6502, Dis6502, Distella, The UK Mirror Service - Acorn Disassemblers
2500AD Simulator-Debugger
Includes disassemblers for many micro-processors, by Avocet Systems.
M68HC11 Simulator
Have 68HC11 Disassembler by Rijswijk Institute of Technology.
Tom's Timex Page
Contains two 6805 disassemblers by Tom Johnson.