Tumbleweed:
Mixania,
Actually, the pull up resistors need to go to the 5V supply pin on the Uno. You need to leave the ground connected to the Uno though, and you will need to power the ATTiny. Since they draw so little current I usually use the 5V pin on the Uno for that too when prototyping. Don't forget a .1uf capacitor between the ground and power of the ATTiny, for noise decoupling.
TomJ
Awesome, thanks! You were very helpful!