Roomba + Wii remote + Perl = Awesome
Anonymous Wii Lov'n Coward writes "Check out the WiiRoomba, a mashup using a Wii remote, a perl script, and the Darwiin Remote software. While a little sluggish to respond, the Roomba is entirely controlled by the Wii remote accelerometers." All of the source code to do it yourself is available at the site linked, along with a youtube video of how it works.
For those interested, the WiiLi.org Wiki is full of Wiimote examples using Python, just takes a handfull lines of code to get started with the Wiimote, its really easy.
No offense, but Java would be a particularly bad choice for this application. The real work done here is "gluing" two things together at a system level - the Roomba program and the Wii program. Java is uniquely miserable at interacting on the system level. Where Java excels is object-oriented architectural design and huge enterprise-level programs.
So, if you want a scalable application server, use Java. If you need to tie two programs together, use a scripting language like Python or Perl. If you know you can limit yourself to a Unix shell environment, Perl may be best (and this is from a Python junkie!)