There's a relatively comprehensive guide on Wikipedia.org which Uno-chan rule designs are based on, or you can check out the following:
UNO IN A NUTSHELL (Source)
Each player is dealt 7 cards with the remaining ones placed face down to form a DRAW pile.
The top card of the DRAW pile is turned over to begin a DISCARD pile.
The first player has to match the card in the DISCARD pile either by number, color or word.
For example, if the card is a red 7, player must throw down a red card or any color 7.
Or the player can throw down a Wild Card. If the player doesn't have anything to match, he must pick a card from the DRAW pile.
If he can play what is drawn, great. Otherwise play moves to the next person.
Once a player has no cards left, the hand is over. Points are scored (see scoring section) and you start over again. That's UNO in a nutshell.
OBJECT:
Points are scored by ridding yourself of all the cards in your hand before your opponent(s).
You score points for cards left in your opponent's hands.
Cards as follows:
19 Blue Cards - 0 to 9
19 Green Cards - 0 to 9
19 Red Cards - 0 to 9
19 Yellow Cards - 0 to 9
8 Draw Two cards - 2 each in Blue, Green, Red and Yellow
8 Reverse Cards - 2 each in Blue, Green, Red and Yellow
8 Skip Cards - 2 each in Blue, Green, Red and Yellow
4 Wild Cards
4 Wild Draw 4 cards
WHAT WORD CARDS MEAN
Draw Two Cards - When this card is played, the next person to play must draw 2 cards and forfeit his turn.
Reverse Card - Simply reverse direction of play. Play left becomes play right, and vice versa.
Skip Card - The next player to play loses his turn and is "skipped." Mighty clever.
Wild Card - This card can be played on any card. The person playing the card calls any color to continue play, including the one presently being played if desired. A Wild card can be played even if the player has another playable card in his hand.
Wild Draw Four Card - This is the best, meanest, most sneaky card to have. Not only does the player get to call the next color played, but the next player has to pick 4 cards and forfeit his turn. There is a hitch, however (of course): you can only play this card when you don't have a card in your hand that matches the color of the card previously played.
Note: A player may have a matching number or word card of a different color in his hand and plays his "Wild Draw Four" card.
SCORING
When a player is out of cards, he gets points for cards left in the opponent's hands as follows:
All cards through 9 Face value
Draw 2 = 20 points
Reverse = 20 points
Skip = 20 points
Wild = 50 points
Wild Draw 4 = 50 points
