I have a power amplifier (powerpod 1860 deluxe) that is rated at
260Watts per channel at 8ohms and 400Watts per channel at 4ohms.  If I
connect two 8ohm speakers in parallel to each channel this drops the
total impedance per channel to 4ohms.  Does this mean that each
speaker has to be capable of handling 400Watts or does the power split
between them (ie. 200W each)?

If everything is exactly balanced, the power will split evenly between
the speakers and you will have 200 Watts per speaker. Nothing is ever
perfectly balanced, so you had better rate them higher than that.
Also, if you have a bad connection in one of the speakers, the other
will be driven alone and could consume as much as 260 Watts. Also, the
amplifier could well be capable of putting out more than the rated
power. I would at least want to be sure the speakers could take 300
Watts each and I would recommend putting fuses on them.

Thanks very much.