Here is the section where you can find all of the information on Hogwarts and it's houses.
Gryffindor
Common Room: a tower on the 7th floor
Apperance: round, red in color, full of fluffy, squashy armchairs and couches, tables, a fireplace, and a message board
Guard: The Fat Lady (a portrait) who requires that you should give the password to enter
House Mascot: a lion
Ghost: Sir Nicholas De- Mimsy Porpington (Nearly Headless Nick)
Head of House: Minerva Mcgonnagal, the Tranfiguration teacher at Hogwarts
Founder: Godric Gryffindor
House Colors: red and gold
Designated For: brave -- The Sorting Hat: "You might belong in Gryffindor, where dwell the brave at heart; their daring, nerve, and chivalry set Gryffindors apart"
Members
During Harry's time at Hogwarts:
Lavendar Brown
Katie Bell
Colin Creevy
Denis Creevy
Seamus Finnigan
Hermione Granger
Lee Jordan
Angelina Johnson
Neville Longbottom
Harry Potter
Parvati Patil
Alicia Spinnet
Dean Thomas
Ron Weasley
Percy Weasley
Fred Weasley
George Weasley
Ginny Weasley
Oliver Wood
Romilda Vane
Before Harry's time at Hogwarts:
Sirius Black
Albus Dumbledore
Lily Evans (Potter)
Rubeus Hagrid
Remus Lupin
Minerva Mcgonnagal
James Potter
Peter Petigrew
Arthur Weasley
Bill Weasley
Charlie Weasley
Molly Weasley
Ravenclaw
Common Room/Appearance: decorated in house colors on walls. Silk coverings on walls. There is a midnight blue carpet decorated with stars. The room is a domed shape room with stars on the ceiling. This is the only house with a statue of its founder in it. There are big arched windows with a spectacular view of the mountains on the west side of the castle. There are the usual bookcases, chairs, and tables in the common room. There is a door leading to the dormotories, beside this is the statue of the founder with her diadem (the statue is life-size and made of white marble).
Guard: The knocker on the door requires that you should give the correct answer to a riddle to enter. If you get it wrong, you have to wait for someone else to come and give the correct answer.
House Mascot: an eagle
Ghost: The Grey Lady SPOILER ALERT----------(the Grey Lady is actually the daughter of Rowena Ravenclaw, the founder of the house, she was murdered by the Bloody Baron)
Head of House: Filius Flitwick, The Charms teacher at Hogwarts
Founder: Rowena Ravenclaw
House Colors: Blue and Bronze(in the movies it is blue and silver)
Designated For: Smart wizards and witches-- The Sorting Hat: "Or yet in wise old Ravenclaw, If you've a ready mind, where those of wit and learning will always find their kind."
Members
Past and Present:
Helena Ravenclaw
Filius Flitwick
Moaning Myrtle
Terry Boot
Eddie Carmichael
Cho Chang
Penelope Clearwater
Michael Corner
Roger Davies
Marietta Edgecombe
Anthony Goldskein
Luna Lovegood
Padma Patil
Slytherin
Common Room: in the dungeons underneath the Black Lake
Apperance: full of skulls and such, the light is green since it is underneath the Black Lake, green couches and armchairs
House Mascot: a snake
Ghost: The Bloody Baron
Head of House: Severus Snape, the Potions teacher at Hogwarts
Founder: Salazar Slytherin
House Colors: green and silver
Designated For: great wizards -- The Sorting Hat: "Or perhaps in Slytherin, you'll make your real friends, those cunning folk use any means to acheive their ends"
Members
Past and Present:
Millicent Bullstrode
Vincet Crabbe
Gragory Goyle
Draco Malfoy
Pansy Parkinson
Blaize Zabini
Lucius malfoy
Tom Riddle
Horace Slughorn
Severus Snape
Hufflepuff
House Mascot: a badger
Ghost: The Fat Friar
Head of House: Ponoma Sprout, the Herbology teacher at Hogwarts
Founder: Helga Hufflepuff
House Colors: yellow and black
Designated for: loyal--The Sorting Hat: "You might belong in Hufflepuff, where they are just and loyal, those patient Hufflepuffs are true and unafraid of toil;"
Members
Past and Present:
Hannah Abott
Susan Bones
Cedric Diggory
Justin Flinch-Fletchy
Ernie Macmillan
Zacharias Smith
Ponoma Sprout
Nymphadora Tonks