I thought it may be worth mentioning about a new serial colour display, it has IO's with PWM and ADC functionality which are accessed via a serial connection so a robot could have a moving face and be controlled by the display either with a wired connection or RF boards like the ones from active robots.
The website address is www.picolour.com
where the unit is about £52.
There are also a quantity available on ebay for £40http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=180359294685&ssPageName=ADME:B:EF:GB:1123
They are designed and made in the UK by the company I work for so the support will be very good, I'd love to see robots with moving mouths and blinking eyes so hopefully there are some robot builders out there who could do this and send back some pictures or video.
They are going to and give away prizes and feature the most interesting applications on the PICOLOUR website which sounds pretty cool.