(Just so you know, some of these are taken directly from the books. Also, Nightpaw is after one of my cats, Ringo.)
THUNDERCLAN
LEADER: Firestar – very old flame-colored tom
DEPUTY: Redstripe – reddish tabby tom, great-grandson of Firestar
MEDICINE CAT: Leafpool – aging tabby she-cat with amber eyes APPRENTICE, JAYPAW
WARRIORS
Squirrelflight – dark red she-cat, green eyes, a senior warrior
Lionfur – golden tabby tom with amber eyes
Hollywhisker – black she-cat with green eyes APPRENTICE, LICHENPAW
Berrytail – creamy tom
Cinderfoot – gray tabby she-cat
Mousepelt – gray-and-white tom APPRENTICE, BUMBLEBEE
Sparkfur – fiery scarlet tabby she-cat, great-great-granddaughter of Firestar
Birchfall – light brown tabby tom
Brook Where Small Fish Swim (Brook) – brown tabby she-cat, formerly of the Tribe of Rushing Water
Stormfur – dark gray tom with amber eyes, formerly of RiverClan
Whitewing – white she-cat with green eyes
Millie – silver tabby she-cat, former kittypet, blue eyes
Poppypatch – tortoiseshell she-cat
Hazelpounce – small gray-and-white she-cat
Flowersong – gray she-cat with blue eyes, Redstripe's mate, formerly of RiverClan APPRENTICE, NIGHTPAW
Blackfoot – gray black-footed tom, green eyes
Iceclaw – white she-cat
Foxshadow – reddish tabby tom
APPRENTICES
Jayleaf – gray tabby tom with blue eyes
Lichenpaw – gray she-cat with one black paw and green eyes, Blackfoot's younger sister
Bumblebee – former loner, golden tom with black stripes
Nightpaw – completely black she-cat with a white ring around one eye
QUEENS
Honeyheart – light brown tabby she-cat, heavily pregnant with Mousepelt's kits
ELDERS
Dustpelt – dark brown tabby tom
Sandstorm – pale ginger she-cat
Cloudtail – long-haired white tom
Brackenfur – golden brown tabby tom
Sorreltail - tortoiseshell-and-white she-cat with amber eyes
Thornclaw – golden brown tabby tom (Whoa! Brackenfur has his same description!)
Brightheart – white she-cat with ginger patches
Ashfur – pale gray (with darker flecks) tom, dark blue eyes
Graystripe – long-haired gray tom
SHADOWCLAN
LEADER: Russetstar – dark ginger she-cat
DEPUTY: Snowbird – pure white she-cat
MEDICINE CAT: Tigerstripe, son of Tawnypelt; tabby tom
WARRIORS
Flametail – reddish tom APPRENTICE, MOUNTAINPAW
Owlpelt – gray tabby tom APPRENTICE, LIZARDPAW
Ivyleap – green-eyed brown tom
QUEENS
Dawnbreath – beautiful tortoiseshell she-cat with a ginger patch and green eyes, pregnant to Owlpelt's kits
ELDERS
Tawnypelt – tortoiseshell she-cat
Oakfur – small brown tom
WINDCLAN
LEADER: Onestar – brown tabby tom
DEPUTY: Harenose – white tom APPRENTICE, GRASSPAW
MEDICINE CAT: Barkface – very ancient short-tailed brown tom APPRENTICE, KESTRELFLIGHT
WARRIORS
Heatherwhisper – (I forgot what color!) some-colored she-cat with blue eyes APPRENTICE, RABBITPAW
Breezeclaw – white tom
Nightcloud – black she-cat
Owlwhisker – light brown tabby tom APPRENTICE, OSPREYPAW
Crowfeather – dark gray tom
QUEENS
Whitetail – small white she-cat
ELDERS
Weaselfur – ginger tom with white paws
Tornear – tabby tom
RIVERCLAN
LEADER: Mistystar – gray she-cat with blue eyes APPRENTICE, FISHPAW
DEPUTY: Graywater – puddle-gray tom
MEDICINE CAT: Willowfur – (GAH! Forgot again!) some-colored she-cat APPRENTICE, MALLOWPAW
WARRIORS
Minnowtail – gray tom with pale gray-green eyes
Flintclaw – silver tabby tom with crystal blue eyes
Reedfoot – lanky brown tom APPRENTICE, STRIPEPAW
Pouncewater – brown tom
Pebbleleg – black she-cat
Browntail – brown tom with a large nick in his ear
Waterwind - a sleek black tom
Silverfur – silvery she-cat
Sneezemuzzle – gray tabby tom
QUEENS
Larkrose – red-and-white she-cat
ELDERS
Mothwing –dappled golden she-cat
Blackclaw – smoky black tom
Voletooth – small brown tabby tom
Dawnflower – pale gray she-cat