How does a two-transistors LED flasher (flip-flop) circuit work?

[zerobigright]

I don't know when does a capacitors and the transistors switch and turn the other off considering the voltage across them...well, on other words, don't know what makes the LEDs do the flipflop thing...HELP

 

[ranger]

This is a nice little project with a description on how the circuits works:
http://www.talkingelectronics.com/Projects/FlasherCircuits/Page83FlasherCircuitsP1.html

 

[zerobigright]

Thanks, this really helps.