IR Transmitter

Can anyone pls explain this IR transmitter?

Parts:

R1____________22K 1/4W Resistor
R2____________1 Meg 1/4W Resistor
C1_________0.01uF 16V Ceramic Disk Capacitor
Q1____________2N2222 NPN Silicon Transistor
Q2____________2N2907 PNP Silicon Transistor
LED1__________Infa-Red LED
S1_____________SPST Push Button Switch
B1_____________3 Volt Battery

it's just an oscillator that uses PNP and NPN trnsistors.
the R/C is probably selected to make it 38kHz which
is common for IR.