Are you talking about something to put the wood on? Like andirons, but also with cross pieces?

Yes, you want the narrow part towards the back, similar to the shape of the fireplace (or most). I would leave an inch or two of clearance at the rear at most. Depending on how big your fireplace is, several inches on either side is good--that way you have room to maneuver logs. It doesn't need to be the full width of the fireplace.

I think cast iron is pretty standard material, and is fine. They do wear out from heat. Home depot among other places has them for not that much money ($30-50)

Thanks for the answer. I got a cast iron grate and put it into the fireplace as you described. Now I need to get some wood to burn.

Dang, too late.

I have one of these and I highly reccomend it:

Here is a link that might be useful: Grate Wall of Fire

Thanks for the information anyways, seems like something down the road I'll be interested in.