Help putting together Power Supply

I bought all the stuff I need to build my own PS and I think I
understand most of it, but I'm a little unsure about how to hook up
my transformer(s). I bought 2 of these transformers:

http://www.logiccooling.com/images/xform.jpg

I wasn't expecting there to be 3 wires on each side. I want to run
110V, not 220V. Should I just use the 110V and the common on one
side, and the corresponding 12V and common on the output side?

Also, I've got 2 of each part (xformer, rectifier, 27,000 uF caps).
Would it be better to wire 2 completely different power supplies and
then run their outputs in series to get the desired voltage? Or
should I wire the Xformers together internally for the higher voltage?