Here are some example games:
http://www.teamliquid.net/tlpd/korean/games/125078_Bisu_vs_Last/vod
(4 zealot)
http://www.teamliquid.net/tlpd/korean/games/116555_Bisu_vs_Light/vod
http://www.teamliquid.net/tlpd/korean/games/105192_Bisu_vs_firebathero/vod
http://www.teamliquid.net/tlpd/korean/games/104408_Horang2_vs_Light/vod
8 pylon
10 gate
12 pylon
12 zealot (1st)
17 zealot (2nd)
19 pylon
20 gas
20 zealot (3rd)
23 cyber
24 put 3 on gas
24 zealot (4th) Only if Rax expand. Otherwise wait.
(Below assumes he didnt rax expo)
25/33 You have 270 minerals, 70 gas, cyber is at 80 percent. You are not making a 4th zealot.
26/33 pylon
27 goon (1st)
29 range
30 send probe to nat
31/41 nexus (starts a second before the goon finishes)(if vult is coming, wait a tick for your goon to cover the probe)
32/41 goon (2nd)
34 pylon
36 goon (3rd)
38 robo
39 send probes to nat
40 goon (4th)