Each simulated cell is 2048x2048 cells large. With Golly you can run fairly large-sized patterns... but, it's only feasible to run with the HashLife algorithm, which cheats by memoizing the evolution of Life patterns rather than simulating every cell. Golly includes a few patterns using OTCAMP as samples.
(I totally need to upload my PokerStars icon here, if I can remember where I put it...)