Book / Docs recomendation for getting going on embedded Linux ?

Hi,

I have been programming embedded systems without any OS for quite a
number of years now. (From 8bit - up to 32-bit ). I am now looking at
doing my first Embedded Linux based project. I have bought a UNC20
development system (Net+ARM with uLinux), and want to get one or
more good books to get started.
I have been using cygwin for the last 2 years or so, so I am quite
familiar with bash etc.  Initiallly I only need to get a console app
going that has one or more periodic tasks, and that can talk to
another system via a standard asynchronous serial port every 20
milli-seconds. Packet sizes for the comms are maximum 40 bytes,
and I need to maintain a transmit jitter of less than 1ms.
If I can do this with "Standard" system support, then it would be
great. Any pointers gratefully received.

Regards
   Anton Erasmus