This is a push-pull amp, but its not a config I've seen before but its easy to figure out.
Because the output of the op-amp is grounded, op-amp has essentially become a constant current driver, where the current being sunk to ground is proportional to the voltage into the non-inverting input of the op-amp.
The current is being pull through the op-amp from the power supply rails, which has a 130OHM resistor in series. These resistors are also across the Base-Emitter junctions of the two TIP transistors. So essentially you have to pick the resistor value so the current being pulled through the op-amp supply lines is within the linear region for a Vbe of the TIP transistors.
So transistor theory will tell you that for a small change in Vbe, you get a current flow, Ic+Ib into the speaker.
that's as best and brief as I can describe, if you don't know any transistor theory, I'd do some homework.
as stated before me, its not stable, but you can get a lot of power.