Just for my personal interest: today we had a short demonstration of the mechanical arm embedded in an Axiom machine (Affymetrix) and I wondered how one should start to build such kind of tool (say, a simple arm moving a P96).
Does the producers use some kind of standard API ? Is there a standard API to connect to a simple device ? for which programming language ? On the web, one can find the instructions to build a PCR machine, where can I find the instructions to build a robot ? Do I need to be a skilled electrician (I'm not).... etc.. etc...
Long back, I have worked on a automated implementation for patch-clamp experiments using Labview. I remember it was more like a Visual Basic programing, driven using a GUI.
You may also check Matlab or open tools like Scilab or Octave.
See: Scilab robotics toolbox here and Octave robotics toolbox here.
Most people I know who have build robots for biology have used LabView to interface with the machine, often via the serial (RS232) port. It has an advantage of being able to collate and summarise/plot data in the package as well.
Arduino looks nice, thanks for the heads up.
Have you looked at lego technics? (I'm serious!) Some of the kits look pretty cool, nice API and I'm sure it could be bodged for biology applications. Might be a problem justifying it on a grant though :>
You can also have an entire Linux Distribution running on (7.62cm)^2 and talk to controllers via USB/RS232: http://beagleboard.org/
You could ask these guys: http://www.youtube.com/watch?v=BGgcGF1WAD0
cool stuff!!!!! (had to add the additional ! for reaching the lower character limit ;-) )