Bert,
Scanned that article briefly. This is what I know about Pu-238:
It is an alpha emitter with a decent output of energy (heat) that can be used for electricity in thermoelectric/ionic devices, but with a relatively low half-life of 87 years (compared to the 24000+ year half-life of Pu-239) . I don't think this is the same isotope as is used in our current weapons (I think that is the 239 isotope), but I do know that it is currently used in satelites or probes that are too far from the sun to harvest solar power. My guess is that it is just being investigated as a source of energy, although I am not sure that it is a very cost-effective means of energy generation on any sort of large scale as the production of Pu-238 is ridiculously expensive (basically have to get neptunium 237 to accept a neutron) not to mention that it decays to uranium-234 so you have to account for radioactive disposal of the waste products as well. I'd be interested to hear what anyone else knows...if I get a chance I'll try to dig up some info on it for you if you want.
