First of all open the conole by pressing "º" (this only works for pc, in ps3 and 360 there arent any cheats, yet)

Console cammands that need a target (just click the target ,with the console open, that you want to)

Setav #: this will increase any skill

setav health 300: will change the targets health to 300
setav stamina #
setav magicka #
setav smithing 100: will chenge the targets skill in smithing to 100
the skills are:

smithing = smithing
heavy armor = heavyarmor
block = block
two handed = twohanded
one handed = onehanded
archery = marksman
light armor = lightarmor
sneak = sneak
lockpicking = lockpicking
speech = speechcraft
alchemy = alchemy
conjuration = conjuration
illusion = illusion
destruction = destruction
alteration = alteration
restoration = restoration
enchanting = enchanting

setscale #: is used to make npc bigger. 1 is normal 10 is the maximum
kill: the word says it all doesnt it?
resurrect: WARNING by using this you are restoring its inventory to default
removeallitems: it removeal all the items to oblivion, i mean they just disapear.
removeallitems: player it steals all the items from the npc, they dont disapear.
resetinventory: if this will reset the npc inventory to the default inventory.
reserhealth: this will recover the targets health, its like a ultimate healing potion.

all the codes listed above are for npc (non playable characters) now we will start with the codes for objects.

setownership: this will make almost any item yours.
duplicateallitems: this works with chests,urns,barrels and npc.
unlock: this will unlock any door or chest you target.
lock: this will lock an unlocked door, lock level is between 1 (novice) and 1000 (master).

Now we start with the codes that you need to have nothing selected.

tgm: God Mode, you will hae infinite stamina, health, magicka, etc.
tai: you kill the AI npc wont do anything, just stand there in there place.
tcai: its like tai but this only affects the fighting npc will do everything exept fight.
tcl: yo will be able to fly and pass trough walls.
killall: you will kill everything around you, i do not know wich is the range of effect but i only know that if you are at the entrace of whiterun near the blacksmith you will kill everything in the town.
tmm,1: shows all the map tmm,1 activates it and tmm,2 desactivates it.
player.setav carryweight #: set your own point of carriyng.
player.setav smithing #: sets your skill in smithing to the number you replace the # for, use the skills listed in the npc part for this.
player.setav health #: set your health
player.setav stamina #
player.setav magicka #
player.setav dragonsouls #: changes your dragon souls to the value you put.
player.teachword #: adds words of power to your character, change the # for the id found in this page http://elderscrolls.wikia.com/wiki/Console_Shout_Codes_%28Skyrim%29 , though you will need dragon souls to unlock the shouts.
player.setscale #: changes your size.
player.setrace #: changes your race (you must have no helmet on, it will bug if you have the helmet on) to anyone you tipe in, jusp pu the name, like: mudcrab, orc, highelf, dragon, etc.
coc qasmoke: it teleransports you to the test room.
coc riverwood: gets you out of the room.
set timescale to #: changes the timescale of skyrim, 1 is real time.
player.additem # $: adds any item you put the id in, change # for the id and $ for the cuantiti you want, use help "item name" 0 to view the id you need to put "".
sexchange: changes your body sex, not your face.
player.placeatme #: places any npc or object you want at your back, change # for the id, if you want more than one item added jus make a space between the id and add the nuber you want.
player.modav smithing 100: WARNING this is a very diferent, thid will give you extra points, not normal ones.
player.addperk #:change the # for the perk id to add it. search perks by using this. help "perk name" 0.
psb: adds all spells.
player.advlevel: this does not add a normal level, it just adds 1 level to your level, if you are lvl 7
and have 4 perks to add, this wont add any perks to add ill just add a level.
tdetect: you will kill the ai detection, just like if you were invisible.
advskill [skill name] #: this will increase your skills normaly.