in my company captain does the initial PA and then the pilot flying does one or 2 more. I try to do one at top of climb giving current altitude and speed (and translate that in to laymans terms of 7 miles up and 6 miles a minute) routing and current expected arrival time. Then at around about top of descent another one giving the weather at destination, again in laymans terms.
Whilst i havn't been doing them for long i'm getting the hang of the spiel and to help me out in the beginning i used my trusty pilots atlas and pen and paper (yes i write them down before talking, much easier).