Tiny open source hackable wifi device:
Meraki Mini:
US$50, size of a playing card.
* 180MHz MIPS CPU (Atheros AR2315 SoC)
* 8MB Flash, 32MB SDRAM
* 60mW 802.11b/g radio
* External RP-SMA antenna connector, internal chip diversity antenna
* 10/100 Mbit/s auto-crossover Ethernet port
* Headers for 3.3v serial port, GPIO pins
* 5.6-18V DC tolerance, for use in developing countries or with batteries
* Power-over-Ethernet support (non-802.3af)
include one 2dBi antenna and a 7.5V DC power supply. The Meraki Mesh firmware is also configured to let users login over ssh and experiment with their own software. Custom USB-serial adapters * designed for the Mini are available though the Summer Beta program.
The Meraki port of Linux 2.6 for the Mini is available at www.meraki.net/linux. It includes a new Ethernet driver and watchdog timer support for the AR2315.
OpenWRT firmware available
* So presumably the serial port is available as a real serial port, not just a programming port.