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