StarCraft provides many Hot Keys to help speed up the building and production phases during gameplay. It is to your advantage to learn them. You will find that you can save a lot of time by eliminating the need to move the mouse to click on a command console button. With practice you should be able to control your forces with your mouse while keeping production going with the use of Hot Keys. Listed below are the Hot Keys for the Zerg race:

S - Select Larva
U - Burrow
G - Guardian Aspect
D - Devourer Aspect
L - Morph to Lurker

D - Drone
Z - Zergling
O - Overlord
H - Hydralisk
M - Mutalisk
S - Scourge
Q - Queen
U - Ultralisk
F - Defiler (Drone is D)

B - Basic Mutation (Buildings)

Then...

H - Hatchery
C - Creep Colony
E - Extractor
S - Spawning Pool
V - Evolution Chamber
D - Hydralisk Den (H is already used for "H"atchery)

Then....

S - Spire
Q - Queen's Nest
N - Nydus Canal
U - Ultralisk Cavern
D - Defiler Mound.

Queen

R - Parasite
B - Spawn Broodling
E - Ensnare
I - Infest Command Center

Defiler

W - Dark Swarm
G - Plague
C - Consume

Because upgrades require more decision making and are not used as often, you might want to learn the building and unit Hot Keys first before trying to learn the Hot Keys to the upgrades.

Hatchery

L - Upgrade to Lair

Lair/Hive

H - Upgrade to Hive
B - Evolve Burrow
V - Evolve Ventral Sacs
A - Evolve Antennae
P - Evolve Pneumatized Carapace

Spawning Pool

M - Evolve Metabolic Boost
A - Evolve Adrenal Glands

Hydralisk Den

M - Evolve Muscular Augments
G - Evolve Grooved Spines
L - Evolve Lurker Aspect.

Spire

A - Upgrade Flyer Attacks
C - Upgrade Flyer Carapace
G - Mutate into Greater Spire

Queen's Nest

B - Evolve Spawned Broodling
E - Evolve Ensnare
G - Evolve Gamete Meiosis

Defiler Mound

G - Evolve Plague
C - Evolve Consume
M - Evolve Metasynaptic Node

Ultralisk Cavern

A - Evolve Anabolic Synthesis
C - Evolve Chitinous Plating