Narnia 2 should be released in May 2008. Its working title is The Chronicles of Narnia: Prince Caspian.
The Narnia movie series is based on a children's-fantasy novel series by C. S. Lewis.
Let's watch a first behind-the-scenes featurette of Prince Caspian:
Andrew Adamson is Prince Caspian's director.
Here the plot:
"One year has passed in our world since the first adventure ended, but in Narnia almost 1,300 years have passed. The villainous King Miraz prevents the rightful king, his young nephew Prince Caspian, from ruling the land of Narnia. Caspian uses Susan's magic horn that was left in Narnia to summon the four Pevensies to help him and a small army of Old Narnians reclaim his rightful throne." (Source: Wikipedia)
Hope this second installment of the Chronicles of Narnia will be more mature than the first one!