Is there a metal outer piece that surrounded the rubber bushings? I've removed the rubber from the arms to install urethane bushings. If so, do I need to remove this outer metal case and how do I do this?

You do have to remove the outer case (they press out pretty easily) as your new bushings will come with new metal cases.

Stick the whole assembly in the freezer the night before installation - in the morning you will be able to push the poly out of the bushing by hand. Keep the poly in the freezer and you will be able to press the new cylinder in place. Once the new cylinder is in, take the poly piece out of the freezer, lube it with the stuff they give you, and push it into place.

I dont have a press. Any suggestions?

I managed to get them out with hammer and chisel

Hammer works just fine, that's what I used. "Press" just sounds better. ;)

I am ready to put my poly bushings in the rear end housing. No press either. So if I put them in the freezer and lube them up with some vasaline or silicone, then can I tap them in with a hammer too? I was able to get the old ones out with a hammer and some heat, but it wasn't pretty. ;)

a vise works good

I did upper A arm bushings on the passenger side this weekend,,,drove em out with a hammer, got em back in with a socket just slightly larger than the rubber,using a vise for support, piece of cake. Had to do the offset shaft thing so I could get the front end aligned right.