According to my experiences,kids like picture,movie,song,and game.So we can use those way,if we want to teach them a new language.It will be more effective ,if we start to teach them in early age,when they began to speak.
We can use flashcard,like in this site: www.first-school.ws/t/alpha_flash1ad.html.
we will found a lot of flashcard there.Or you can create your own flashcard.Just looking for pictures from internet,and then print it on paper.Don't forget to laminate it,so we can use for this flashcard for a long time.
Beside flashcards ,power point program can be a fun way too,you can visit this link:
http://www.mes-english.com/flashcards/animals.php
Or we can use many free educational websites :
www.starfall.com
http://www.fisher-price.com/fp.aspx?st=30&e=gameslanding&mcat=game_infant,game_toddler,game_preschool&site=us
When the kids are ready to write, you can give them worksheets.It can be coloring sheet, writing sheets,counting sheets and more.
But according to me, the best way is just be a fun teacher for them.
OK....Happy teaching........
Hope it can be useful, for you.And keep smiling :)