Shortest Game of Life
Python, 219 chars

I went for maximum golfage, with just enough interface to satisfy the question.

import time
P=input()
N=range(20)
while 1:
 for i in N:print''.join(' *'[i*20+j in P]for j in N)
 time.sleep(.1);Q=[(p+d)%400 for d in(-21,-20,-19,-1,1,19,20,21)for p in P];P=set(p for p in Q if 2-(p in P)&lt;Q.count(p)&lt;4)


You run it like this:

echo "[8,29,47,48,49]" | ./life.py


The numbers in the list represent the coordinates of the starting cells.  The first row is 0-19, the second row is 20-39, etc.

Run it in a terminal with 21 rows and it looks pretty snazzy.