http://physics.stackexchange.com/a/200/7924 gives a competent and fairly complete answer to your question.
Let me add that locality is implemented automatically into the quantum field concept by the demand that the fields satisfy (weak operator) differential equations, which define the changes at some point in terms of values at the same point. Thus the fields in some region (such as those occupied by a particle = a localized lump of energy) changes with time without ever using information from elsewhere except the region itself an its boundary.
The forces are gradients of the fields and are ''there'' all the time with their right strength. The transmission of energy (perceived colloquially as transmission of forces) happens according to the laws derived from the differential equation. This are hyperbolic for systems with finite propagation speeds. This implies that pulses of energy spead in a wave-like manner to everywwhere where they can have an effect.
The transmission is completely analogous to that of gravitational forces by the gravitational field. Thus you can study the details in a framework much simpler than the standard model.