Saving space with strings

Also a diary entry:
How to save space on Strings using the FLASH memory of an ATmega
http://jeelabs.org/2011/05/23/saving-ram-space/

This is a usefull post, but for one thing: it does not explain the PSTR()

This turns out to be handled with a little care, so no

Serial.println(PSTR("hello");

will work, as explained here:

http://arduino.cc/forum/index.php?action=printpage;topic=50197.0

Ad you learn something about addresses and seperate parts of the Harvard architecture