Here is a look at Husky's Zerg Tutorial (for new players). Take a look at the video, it will repay your attention.
Basic Roach opener for Zerg. Great build to own your friends :).
10 3 drones (after Overlord finishes)
13 Spawning Pool
12 2 drones
13 2 drones
18 Roach Warren
19 Inject Larva (always do this ASAP)
19 2x Roaches
21 1x Roach
22 4x Roach
PUSH OUT AROUND NOW. You can get your overlord at 25 if you prefer a more fluid production of roaches.
Continue producing roaches and inject larva.
Macro up and alter your build to counter what your opponent is going.