The Raspberry Pi is a credit-card-sized single-board computer developed in the UK by the Raspberry Pi Foundation. The Raspberry Pi is manufactured in two board configurations. The Raspberry Pi has a Broadcom BCM2835 system on a chip (SoC), which includes an ARM1176JZF-S 700 MHz processor, VideoCore IV GPU shipped with 512 megabytes of RAM. It does not include a built-in hard disk or solid-state drive, but uses an SD card for booting and persistent storage. The Foundation provides Debian and Arch Linux ARM distributions for download. Tools are available for Python as the main programming language, with support for BBC BASIC (via the RISC OS image or the Brandy Basic clone for Linux), C, Java and Perl.

Specification of Raspberry Pi (Model B)
Target price         : US$ 35
SoC                    : Broadcom BCM2835 (CPU, GPU, DSP, SDRAM, and single USB port)
CPU                    : 700 MHz ARM1176JZF-S core (ARM11 family, ARMv6 instruction set)
GPU                   : Broadcom VideoCore IV @ 250 MHz

OpenGL ES 2.0 (24 GFLOPS)

MPEG-2 and VC-1 (with license), 1080p30 h.264/MPEG-4 AVC high profile decoder and encoder

Memory (SDRAM)    : 512 MB (shared with GPU) as of 15 October 2012
USB 2.0 ports            : 1 (direct from BCM2835 chip) 2 (via the built in integrated 3-port     USB hub)
Video input               : A CSI input connector allows for the connection of a RPF designed     camera module
Video outputs           : Composite RCA (PAL and NTSC), HDMI (rev 1.3 & 1.4), raw             LCD Panels via DSI

14 HDMI resolutions from 640×350 to 1920×1200 plus various                                               PAL and NTSC standards.

Audio outputs           : 3.5 mm jack, HDMI, and, as of revision 2 boards, I²S audio(also potentially for audio input)
Onboard storage       : SD / MMC / SDIO card slot (3.3 V card power support only)
Onboard network     : 10/100 Mbit/s Ethernet (8P8C) USB adapter on the third port of the USB hub
Low-level peripherals: 8 × GPIO, UART, I²C bus, SPI bus with two chip selects, I²S audio +3.3 V, +5 V, ground
Power ratings          : 700 mA (3.5 W)
Power source          : 5 V via MicroUSB or GPIO header
Size                        : 85.60 mm × 56 mm (3.370 in × 2.205 in)
Weight                     : 45 g (1.6 oz)
Operating systems   : Arch Linux ARM, Debian GNU/Linux, Gentoo, Fedora, FreeBSD, NetBSD, Plan 9, Raspbian OS, RISC OS, Slackware Linux, OR your own compiled OS (Toolchain in project 9)

Source

http://en.wikipedia.org/wiki/Raspberry_Pi

www.raspberrypi.org