OK some more information:

Arduino code:

char val;
int ledPin = 12;

void setup() {
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  if (Serial.available()) {
    val = Serial.read();
  }
  if (val == 'H') {
    digitalWrite(ledPin, HIGH);
  } 
  else {
    digitalWrite(ledPin, LOW);
  }
  delay(100);
}

Processing code:

import processing.serial.*;
Serial myPort;
println(Serial.list());
myPort = new Serial(this, Serial.list()[0], 9600);
//myPort.write(72);
myPort.write('H');


Also as the code works on Windows I guess the issue must be with my environment:

Current:
Arduino 1.0rc2
Processing 2.0a
SL 6.1 i686
custom avr-gcc-4.3.4 from avrfreaks
java version "1.7.0_01"
Using provided rxtx packages


I have tried other distros, rxtx versions, java versions etc.

Also one more interesting that I home may help a more trained eye then mine:

If I print

Serial.println(10);

Processing reads:
49
48
13
10

Serial Monitor reads:
10

Serial.println('H');

Processing reads:

72
13
10

Serial Monitor reads:
H


====

On further search I found the following:
http://processing.org/discourse/yabb2/YaBB.pl?num=1212498341

The code in reply 3 works fine with Serial.write('H'); and processing picks it up as 72.

That half the battle still not sure what is going on with (processing) port.write(72); (arduino) Serial.read();...

I thought I had exhausted my research on this but still finding stuff.  If anyone can chip in with a write suggestion I would appreciate the time saving.


====

Thanks

Gary

http://blog.re.je/2011/11/11/processing-arduino/