Exactly how you need to set about cleaning wood paneling will to some extent depend on the wood that was used for the paneling and the finish that was applied to it. However, the following should give you more than enough information to at least make a start on cleaning your wood paneling.
Painted Wood Paneling
To start with, and in order to avoid rubbing more dirt into the paneling, using a duster or fine and lightweight brush, remove any surface dust from the paneling. When doing this, do make sure that you clean between the joints, along any seams and adornments to the paneling. If the paneling has an enamel paint surface you can then clean it thoroughly with any detergent or preparatory cleaning agent.