Transferring images onto wood is really a two day process, but you can rush it. The trick is to transfer the ink and remove the paper.
Materials: sanded wood pieces (any shape, but they must be flat and smooth), images printed on a laser jet printer, brushes, and Mod Podge.
Directions: 1. Brush a thick coat of Mod Podge onto the printed side of the paper. 2. Paste the image face-down on the wood and press firmly to remove all the air. 3. Wait overnight (or skip this step for a more rustic look). 4. Wet your finger and rub it gently back and forth over the paper. The paper will ball up and the ink will remain stuck to the wood. Here are some helpful links.
Lengthy and more foolhardy method: http://content.photojojo.com/diy/diy-photo-transfers-on-wood/