Here's a profile of the Ripley wearable computer project.
Initially modeled loosely on Prof. Steve Mann's wearcomps, the
project's gone off on its own direction. The current versions
support the 2.2 or 2.4 kernels, boast speech recognition and a full
complement of applications.
"The Ripley wearable computer project was born in 1999
with the purpose of allowing us to liberate ourselves from the
desktop computer.
Our first goal was to build an anytime, anywhere general purpose
computer that is efficient enough to run on consumer grade
batteries for several hours, small and light enough to wear on the
body, wirelessly connected to the Internet at all times, and easy
to interact with even while doing other things (i.e. non-modality
of computer/human interface).
Existing computing devices, such as laptop computers and PDAs,
were unsatisfactory. Laptops are just small desktop computers with
the same modality of use. Users of laptops need to be in "laptop
mode" -- sitting with the laptop balanced on their laps and their
attention focused on its screen and keyboard. In order to do
something else, they then need to break away from laptop mode --
which makes it difficult to continue to interact with the laptop.
PDAs, on the other hand, were simply not robust enough to handle
most of the situations we envisioned."