Sure, of course you want a Raspberry Pi, be it for running a media centre, teaching computer science, home automation experiments or just for the hell of it. Unfortunately, a few hundred thousand other people also want one — join the queue!
While you're waiting (my Pi should be shipping in an unbearable three weeks), there are plenty of alternatives available if all you're after is a cheap, single-board computer to play with.
The BeagleBoard is probably the most famous hobbyist-friendly, single board computer available. It costs US$149 and has an open source design. The Linux-friendly system is USB powered and runs a Texas Instruments OMAP 3530 system-on-a-chip (SoC), which has a 600MHz ARM Cortex A8 processor. The board includes 128MB of RAM and 256MB of flash storage. Output is via DVI=D or S-Video, so it can be hooked up to a monitor or TV easily. It also has stereo outputs and inputs, a USB 2.0 port and a serial port. It measures 3.4-inches by 2.1-inches (about 8.6cm by 5.3cm, about the same size as the Raspberry Pi).
Also available are the BeagleBoard-xM, which has 512MB of RAM and a 1GHz Cortex A8 and the BeagleBone, which uses TI's Sitara AM335x and can be hooked up to a BeagleBoard or BeagleBoard-xM.
The UzeBox is an open source games console based on a single board. Its designer, Alec Bourque, describes it as a "retro minimalist" console, designed for those with fond memories of 8-bit gaming. It uses an ATmega644 microcontroller and has 4KB of RAM and 64KB of flash storage. Its design is licensed under version 3 of the GNU GPL. You can purchase non-assembled and assembled UzeBox kits. "The main design goal was to keep it simple so it would be easy to understand and assemble by hobbyists," Bourque told me in a lengthy interview I conducted last year.
Arduino is a well known open source microcontroller platform with a stack of accessories available for it. (You can watch an entire documentary about it if you want to.) Use it for knitting. Use it for rocking out with pyrotechnics. Use it for pretty much anything you can imagine. You can pick up the Arduino Uno reference board for $37. It's based on AVR's ATmega328 microcontroller.
For just over $170 you can pick up a PandaBoard. It's a mobility-friendly single-board computer based on the TI OMAP4430 SoC, and includes HDMI out, 10/100 Ethernet, Wi-Fi, Bluetooth and multiple USB connectors.
Gumstix offers a range of single-board systems. The designs are not open source, but the systems are Linux-friendly. The Gumstix Overo Earth COM is available for US$149 for single orders. Like the BeagleBoard it runs a TI OMAP 3503 SoC. It has 512MB of RAM and 512MB of flash. The company offers a range of expansion boards to add features such as Ethernet, imaging and GPS.
Okay, so you can't get your hands on one yet, so it's not really an alternative, but it's still an interesting offering: Via has announced a US$49 computer that will run Google's Android platform. The device won't be on sale until July, according to Via. It includes 512MB of DDR3 RAM, 2GB of flash storage and has HDMI out, D-sub/VGA, four USB 2.0 ports, audio jacks, Ethernet, and a microSD slot. The APC will use VIA's own 800MHz processor and run a version of Android 2.3 at launch. It measures 170x85mm.
If you're resigned to pre-ordering a device, you can consider the MK802. Like the APC, it runs Android — but in the case of the MK802, it's version 4.0 of Google's mobile platform. The device is available for US$74 and runs a 1.5GHz AllWinner A10 Cortex A8 ARM processor and has 512MB of RAM and inbuilt Wi-Fi, USB ports, 4GB of flash memory, a microSD card slot, and HDMI output.
Of course, if your heart is set on a Raspberry Pi, you better get cracking and order one right now. RS Components is offering it for US$35 (including postage to Sydney, it worked out at US$43.02 for me).