What package type, DIP or SMD?
Big or Tinny
If its DIP , like the one Radio Shack sells then 30k and 191. If you search my tuts you can find links to Mouser or DigiKey if you live in the US. If not I can't direct you, but I'm sure someone else can..
If your using SMD then that's different.. For example I have installed in my Slim the original pre production sound board. IE the little board with SMD LM386 and SMD 191k and 30k resistors and it works flawlessly. However others that have bought the soundboard for install in a slim from the production run have had problems with the leds not blinking.... However in a phat I think it works fine. I can't tell you as I have never had a problem with ether...
I will say this (and I know your installing in a PHAT so this is just general info)
Turns out the the lm386 that I received when testing the soundboard were manufactured by another company and maybe that is why mine work and others don't..