All you need is a light like this:

Available for example at IKEA (click here) for 14,95 €. This lamp you can mount directly at you Table Soccer and adjust it over the center of the table. We are using this kind of light at the Garland tables and it just works perfect. It gives the whole game much mur quality when you have a good light and this option is ealy to mount and dismount in case you want to use it only for a evening in a bar.

Pictures from a Garlando table: