Linux appliance?

[Michael ODonnell]

Here's a query direct from a German relative when he
heard that I know something about Linux:

 [my mother] is dying to be able to use the Internet, but is
 very afraid of computers.  At home she cannot even correctly
 use her cell phone or Funktelefon.  Isn't there a simple
 little Idiot-proof LINUX- Systeme bootable from something
 like an e-prom which cannot be invaded by viruses, trojans,
 dialers, spyware, etc?  (Sort of like the old ATARI-PC?).
 That would be a super sales hit for our parents, in fact a
 "business idea."  Don't you think so?  I herewith establish
 my claim as being first with this idea.

Any recommendations?