Originally posted by LA Marlowe:
Yes, if you run the new toilet drain out of pvc, you will need a no-hub gasket to connect to the cast iron. They are also used to connect two pieces of cast iron pipe when one of them does not have a hub at the end for inserting the other, hence the name. (That is a long way of saying that if you cut the pipe and then change your mind, you can connect the two cut ends again with a no-hub, so long as the pipe didn't shatter when you cut it.) Here is a link with some pictures, and a better explanation than I can give:
http://www.askmehelpdesk.com/plumbing/connecting-pvc-cast-iron-56384.htmlThe tub drain should tie in quite nicely with the new pvc using a standard Y fitting.
If you've never done this type of plumbing before I would recommend you at least call and get some estimates on having it professionally done. It is not technically difficult, but can be quite daunting if you've never attempted it before.
Best of luck to you!