I am wondering i just recieved the arduino duemilanove with thewith the atmega/328 and I just plugged it in and the L Led is blinking and won't stop is that normal?
Yes. If you knew morris code, you could tell that it was saying "Hello."
Sketches or code on microcontrollers runs continuously. They are not like computers with a concept of starting/stoping "programs."
You mean morse code? 
and only the uno says something - the duemilanove just blinks (as far as I know)
Correction: Sketches or code on microcontrollers Arduinos runs continuously.
Don