hey try these LED flasher circuits,they are nothing but square wave oscillators, to adjust the flashing period, we've to vary the duty cycle.....

 

Or, if you don't mind fiddling around a little bit to get it working, here is the simplest (parts count-wise) flasher:

http://cappels.org/dproj/simplest_LED_flasher/Simplest_LED_Flasher_Circuit.html

 

This is my favorite. I miss the LM3909 though, I like the D cell battery concept..

I think it compares pretty closely if you remove one of the LED legs parts wise. A transistor is simpler than a chip though.

 

You can still find the 3909 on Ebay every now and then. Kind of pricy though. I have 3 still laying around, actually in use at the moment.