Tomatoes, as well as other members of the Solanaceae require a special kind of pollination to achieve proper fruit set. This form of pollination is known as "buzz pollination". Buzz pollination is accomplished by Bumblebees (Bombus), by gripping the flower with their legs and vibrating their flight muscles, honeybees (Apis) are incapable of doing this. In small gardens, bumblebee populations can be insufficient to properly pollinate tomatoes and related plants. Here's how to buzz pollinate your plants to produce larger fruits.
Step 1: Yes, this is a one step instructable
You will need an electric toothbrush with soft bristles. The electric toothbrush I'm using retails for $5 and after six months is being retired.
To pollinate the flower, turn on the toothbrush and gently and briefly touch it to the petals or stem of the flower, or flower cluster. Do not touch it to the face of the flower. That's all that is required, simply keep the toothbrush in with your garden tools and spend a few seconds each time you visit the garden, the results will be worth it.
Original article and pictures take http://www.instructables.com/id/Pollinating-Tomatoes/ site