Exactly like the PICAXE-28X1, this the tiny SOIC 300mil version, suitable for surface mount (tiny robots!) projects.

The PICAXE-28X1 is a new revision of the popular 28 series, with way more memory, many more I/O, and supporting I²C! Now you’re working with a pretty powerful micro, and still not having to crack a book on “C” programming!

The PICAXE system is a powerful, low cost microcontroller programming system designed to simplify educational and hobbyist use of microcontrollers. PICAXE chips can be programmed in a graphical ‘flow-chart’ environment or in easy to understand BASIC.

Features:

• 1000 lines memory
• 0-12 Inputs
• 9-17 outputs
• Hardware I²C support for easy peripheral connecting
• Internal Timer
• Increased variables and separate memory scratchpad
• Enhanced mathematical functions
• 0-4 8/10-bit Analog-to-Digital converters (ADC)
• 20MHz maximum operation speed (4MHz normally)
• Line-by-line simulation
• Supports 
  • Interrupts
  • 12-Bit Digital temperature sensors
  • Servo control
  • Keyboard input
  • IR transmit/receive
  • Plays user-defined musical tones
  • PWM Motor control
  • Input Pulse counting
  • Serial output & debugging via programming cable
  • Higher baud rate for serial work
• Based on the PIC 16F886 IC

Memory (lines) = Approximate number of lines of program code the chip can hold.
Data Memory = Bytes of EEPROM memory on board (128-Prog means 128 Bytes less the space needed for your program. 256+I2C means 256 Bytes + any external EEPROM space you add via the I2C interface).
Polled Interrupt = A process that automatically checks a pin in between each command to see if something has happened (very useful!)

Resources:

PICAXE Manual Part 1 – Getting Started (.pdf)
PICAXE Manual Part 2 – BASIC Commands (.pdf)
PICAXE Manual Part 3 – Interfacing Circuits (.pdf)
Programming Editor (.exe)