Lpc2000

Anybody here ever seen (or done) an IAP flash programming app that
re-loads flash with updated code that the end user downloads from
their PC ?
  I would think one could do this without too much trouble on
an LPC2XXX and might even fit into one sector.
Un-encryption of the downloaded code would be a benefit as well so
code copying wouldn't be so much of a problem.

Maybe there's even some good starting point examples around.

Thanks,
Bob