Obsidian has confirmed that the warlock invocation eldritch blast will be included in NWN2.
By default, eldritch blast has no specific type and is limited to a range of 30', with no saving throw (but spell resistance applies), and has an effective caster level of 1. Eldritch essence & blast shape invocations will modify the effects of the blast. This usually increases the ECL. If it has an additional effect that applies a save, your Charisma modifier will be applied to the DC.