Just finished adding two preposition activities to TpT and WorksheetShare.com. A prepositions crossword puzzle and a prepositions word search. The crossword puzzle even comes with an answer key when you purchase it from TpT. I plan on adding an answer key to the word search later. Both activities are designed to go along with the Easy Grammar® series by Dr. Wanda C. Phillips.
If you are not familiar with Easy Grammar® texts they use the prepositional approach combined with effective strategies. I personally have found the text quite effective in the classroom.