Here is various information about the Propeller architecture and various boards that have a Propeller on them.
Propeller P8X32 die
Architecture Information
The Propeller P8X32 chip is a multicore microcontroller. It has 8 cores, called Cogs, 32k of shared RAM, 32k of ROM, and 32 I/O pins.
The Cogs each have their own local memory, and share access to the 32k Hub memory. They also share access to the 32 I/O pins. They, also, each have their own pair of user configurable counters with PLLs and a Video Generator that aids in driving either NTSC/PAL or VGA video outputs. Hub RAM - 32K Ram shared by the Cogs Cog RAM - 512 Longs local memory per Cog Oscillator - Options and Over-Clocking Interrupts - Handling 'external signal events' Video Generator - Output Video signals Propeller Data Sheet v1.4 PDF Propeller Application Notes
Development Boards
SerPlug an inexpensive alternative to the PropPlug - program your propeller from a serial port or USB to serial cable.
Chameleon PIC/AVR a multi-processor "Arduino Like" system consisting of either a Microchip PIC24 16-Bit or an Atmel AVR 328P 8-Bit microcontroller and a Parallax propeller.
Morpheus: Dual Propeller SBC with 512KB RAM, 1MB Flash, RTC, 256 color VGA and expansion bus, Mem+ 2MB memory/IO expansion board with RS232 port & programming, SD card support and 16 bits digital I/O
Propteus: Propeller Prototyping Board with support for DIP Propeller, EEPROM, PropellerPlug compatible header, Reset switch, optional 4 user LED's,large prototype area, stacks on Morpheus or other Parallax boards, 12 servo headers, bussed large prototyping area.
Proteus: A bussed prototyping board meant to mount on Morpheus, Propteus, Propeller Proto Board (serial and usb version) or any 4"x3" Parallax style board.
SmorgasBoard 2012: A collection of 23 open source propeller designs in a 11x8", tab routed PCB panel