Akari

[from nikoli website]

1. Place circles according to the following rules.
2. Circles are permitted at any white squares. Each number indicates how many circles are next to it, vertically and horizontally.
3. Each circle 'illuminates' from it to black square or outer frame in its row and column.
4. Every white square must be illuminated and every circle should not illuminate each other.
   

Solution:
It's possible to play online at http://www.puzzle-loop.com/