Earth is the 3rd planet from the Sun and is the 5th largest in the Solar System.
It is the only planet known to support life in the Solar System.

Mars has an ancient
landscape dominated by impact craters. As well as having the tallest
volcano in the Solar System: Olympus Mons, 21 km high and 600km across, it
also boasts the largest canyon system: Valles Marineris, 4000km long and
up to 11km deep.

Jupiter is the most massive
planet in our Solar System and has numerous moons and several rings.
The rings of Jupiter were discovered in 1979 by Voyager 1.
Jupiter has 4 large moons discovered by Galileo,
these are: Io, Europa, Ganymede
and Callisto and are known today as the Galilean
satellites.

Saturn is a "Gas Giant" made up of mostly hydrogen and helium and has a ring system which is the most complex and extensive in the Solar System.
Saturn has more than 30 satellites the largest of which is Titan.
The Cassini/Huygens spacecraft launched in 1997 will reach Saturn in late Nov. 2004 and will spend 4 years studying Saturn, it's moons and rings.

Uranus was discovered in 1781 by Herschel and is classified as a "Gas Giant". It also has rings though very different from Saturn and Jupiter. Uranus also has about 20 moons the largest of which is Titania also discovered by Herschel.

Neptune, since it's discovery in 1846, has not yet made a full orbit of the Sun, this orbit takes 165 years.
Although the smallest of the "Gas Giants" it could hold about 60 Earth's.

Pluto is the farthest planet from the Sun and has a moon that was discovered in 1978. The moon is called Charon and is almost half the size of Pluto. With Pluto being so far from the Earth, no spacecraft has ever visited it.