Word search? As in you have a grid of letters, and have to find words?
I'll assume, just cause it's more awesome, that you want to generate word searches. Well, first off, get your words, and make them appear at random in the grid. Set a starting position, and send the word off in a random direction. Then test if
a) You do not overwrite an existing word, or if you do, that the letter you overwrite is the same as the letter you write.
b) the word does not go off the grid.
Then, fill all the empty boxes with a random letter.
Then, by say clicking and dragging across multiple boxes (with a rule that a box cannot be selected if two of the boxes next to it are selected, for diagonal selection), write the values of the boxes to a variable. If the variable matches one of the words in the word search, hey presto, a point!