Driving 1W LEDs - help with circuit please

I have a PIC (PIC16F688) based controller circuit that drives an LED flasher. The PIC can only handle about 9mA per LED and that is fine for typical LEDs - however for my intended application (the machine guns in the wings of a Radio Controlled Spitfire) I want to use some high power 1W LEDs (3V, 100mA drive)

Now I am clueless when it comes to designing circuits although I do understand how circuits work when drawn out and so I'm hoping someone can give me the basics of what I need to be able to use the PIC output to drive a transistor to switch the voltage needed for the high power LED

I'm assuming that I need some resistors and some PNP transistors but how do I calculate the values? I'll build the circuit on a bit of breadboard and there are 8 LEDs involved, each driven from a separate output line of the PIC

Can anyone help please?

https://www.physics.unlv.edu/~bill/PHYS483/current_lim.pdf

That circuit will work quite well. For a 3 V LED you can driver it from 5 V instead of 12 V. R1 needs to be about 7 ohms for 100 mA.

By the way, 3 V and 100 mA is 0.3 W not 1 W.