Has anyone mentioned Wifi routers and OpenWrt? (Score 1)

If the avenue that the OP is planning on heading down involves tele-robotics with computer vision abilities, I would suggest looking into OpenWrt. I've had great success with upgrading the firmware on various routers and putting them to use in robots (usually streaming video and serial port data back to a PC). It is a very economical way of getting into embedded Linux, and highly recommended if you like to communicate to your robot via wifi. It is not too difficult to setup a cross compiler and develop your own programs to run on the router.

An alternative to hacking a router is something like a Raspberry Pi or a Beagleboard. I haven't used a RPi, but own a Beagleboard and would like to warn you that building an image and setting up a toolchain (using OpenEmbedded to build Angstrom) for a Beagleboard (or Gumstix) is quite a task. It's also pretty difficult to get a suitable usb wifi stick and driver to operate as an access point (something I was convinced I needed!).

As far as microcontroller and platforms go, I would suggest starting off with an Arduino. You could use Arduino's Wiring programming language, but it is just as easy to use WinAVR/avr-gcc/avr-g++, C/C++ and good old Makefiles! After conquering a simple to use microcontroller like an ATmega (used on the Arduino), I recommend you use something like a PIC32 or a STM32 if you need more horsepower. I've used the SAM7 quite a bit but am somewhat reluctantly to do on any new projects.