To the untrained eye the night sky looks patternless but humans like to have patterns so they made the constellations. Different civilisations used different constellations (or patterns) so hundreds of years ago depending on where you went star maps would look very different indeed.

Today's list of recognized constellations was codified in 1930 by the
International Astronomical Union, but records of stellar patterns
dates back thousands of years. The Lion, the Bull and the Scorpion
were recognized by ancients living in the Euphrates Valley by 4000
BC.

But it was during the second century AD that the Egyptian astronomer
Ptolemy listed 48 star groupings visible from his native Alexandria
in his work, the Almagest. New constellations were not recognized
until the 16th Century when European explorers sailed to the southern
hemisphere.

Johann Bayer's star atlas from 1603 included a dozen new southern
constellations.

Jakob Bartsch added three new constellations in the spaces found
between the existing constellations. Bartsch is also credited with
naming Crux, the Cross, by taking four stars from Ptolemy's original
Centarus.

Tycho Brahe is credited with naming Coma Berenices, Berneice's Hair,
which had been previously listed as part of Leo or Virgo.

German astronomer Johannes Hevelius added seven more constellations
in his star atlas of 1687.

In 1750, astronomer Nicolas Louis de La Caille visited the Cape of
Good Hope and drew up 14 more constellations.

Since that time, other constellations have been suggested, but none
were included in the IAU's list from 1930. That list is the standard
still.

If you have any intresting infomation on constellations please post to the forum below.

Here is a list of the 88 (Although one appears to be missing, if you spot which one please let me know!) modern constellations and some infomation on them:- (Z means Zodiacal Constellation, this means the Sun appears to travel through it)

Andromeda

Antlia

Apus

Aquarius (Z)

The Water Carrier - This constellation is depicted as a man
or boy emptying a jar of water, representing the start of the rainy
season.

Aquila

Ara

Aries (Z)

The Ram - The golden fleece of this ram was the prize carried
off by Jason, leader of the Argonauts. It is the first constellation
of the Zodiac.

Auriga

Boötes

Caelum

Camelopardalis

Cancer (Z)

The Crab - Juno sent this crab to attack Hercules while he
struggled with the Hydra. The crab failed in its mission and was
crushed, but as a reward, Juno placed it among the stars.

Canes Venatici

Canis Major

Canis Minor

Capricornus (Z)

The Sea Goat - The last three constellations in the
zodiac are in the region of the sky called the sea. This
constellation is depicted with the head and body of a goat and the
tail of a fish. One explanation is that the goat is an expert
climber, representing the sun's climb from its lowest point in the
sky, which is in this constellation. The fish's tail is thought to
represent the rainy season.

Carina

Cassiopeia

Centaurus

Cepheus

Cetus

Chamaeleon

Circinus

Columba

Coma Berenices

Corona Australis

Corona Borealis

Crater

Crux Australis

Cygnus

Delphinus

Dorado

Draco

Equuleus

Eridanus

Fornax

Gemini (Z)

The Twins - The two brightest stars are named Castor and
Pollux in this constellation. Castor was the son of Tydarus and
Pollux was the son of Zeus, making him immortal. Upon the death of
Castor, Pollux was so grief-stricken that he longed to share his
immortality with his brother. Zeus granted this wish by placing the
brothers together in the sky.

Grus

Hercules

Horologium

Hydra

Hydrus

Indus

Lacerta

Leo (Z)

The Lion - Shaped like a question mark, the tough thick skin of
this lion became Hercules' trademark cloak. He strangled the creature
to death and completed his first labour.

Leo Minor

Lepus

Libra (Z)

The Scales - This stars which make up this constellation were
taken from neighbouring Scorpius. The Arabic names of the two
brightest stars in Libra mean the southern and northern claw. Libra
is often associated with the scales held by Astraea, goddess of
justice, and it was probably created to make 12 constellations in the
zodiac.

Lynx

Lupus

Lyra

Mensa

Microscopium

Monoceros

Musca

Norma

Octans

Ophiuchus

Orion

Pavo

Pegasus

Perseus

Phoenix

Pictor

Pisces (Z)

The Fish - Venus and Cupid escaped from the monster, `Typhon'
by disguising themselves as fish and jumping into the Euphrates River.

Piscis Australis

Puppis

Pyxis

Reticulum

Sagitta

Sagittarius (Z)

The Archer - Associated with the centaur Chiron because
of his marksmanship with a bow, but also because he pointed out the
tea pot shaped grouping of stars to the Argonauts on their voyage to
Thessaly.

Scorpius (Z)

The Scorpion - Apollo was concerned about protecting his
sister Artemis' virginity as the hunky hunter Orion was interested in
her so he sent the scorpion to kill Orion. Both the scorpion and
Orion were placed in the heavens, but as far apart from each other as
possible. The heart of the constellation is the red star Antares,
which literally means Rival of Mars. When the red planet travels
along the ecliptic in Scorpius, you'll understand why the star got
its name. It is actually a binary star which a large telescope will
resolve into a red giant and green dwarf.

Sculptor

Scutum

Serpens

Serpens is divided into two sections that don't touch each other: Serpens Cauda and Serpens Caput.

Sextans

Taurus (Z)

The Bull - Zeus disguised himself as a white bull in rder to
attract Europa, princess of Phoenicia. Drawn to the animal by its
beauty, she climbed upon his back and he swam with her to Crete where
he `revealed' himself and `won' her.

Telescopium

Triangulum

Triangulum Australe

Tucana

Ursa Major

Ursa Minor

Vela

Virgo (Z)

The Virgin - Often associated with Ceres, goddess of the
harvest, the brightest star in this constellation is called Spica,
which is translated as sheaf of wheat or ear of corn.

Volans

Vulpecula