Generally, electron affinity values are given as absolute values, but for most elements, they represent an exothermic process, and are negative quantities of energy.
Since electron affinity relates to the adding of an electron to an atom, and since the electron experiences a net attractive force to that atom, the value of the enthalpy change for the process would be negative (except in the case of the Noble Gases).
When these values are listed in a table of electron affities, however, it is typical to state them as positive numbers (in the sense of an absolute value).
Check out the Wikipedia article relating to this. It is quite good.