301/302 redirects and how to go about them

Hi guys, hope you can help me out with this small conundrum I have gotten myself into.

Registered a domain name http://utahautoscene.com and a few hours later registered the URL http://utahautozine.com.

Basically, first we wanted to use scene than we came up with the idea of zine and thought it would work much better for our needs.

Currently I have http://utahautozine.com redirecting (302 temp redirect) to http://utahautoscene.com.

What I am trying to figure out is this: from my understanding I will need to select one as the primary and market that one since all content links like http://utahautoscene.com/utah-auto-scene-is-coming-soon/ will be through one or the other but not both.

And so I am trying to figure out if by having both up and eventually one with a 301 redirect pointing to the other, how this will work when it comes to content linking. Basically, I don’t want to continuously create 301 redirects for each post that we do on the main URL.

And if this is the case, then one of the addresses becomes basically useless since all it points to is the index of the main site. Is there anyway to have both URLs have the linking structure so they can be indexed by search engines or would this be duplicate content as far as SEO is concerned.

Basically I want to have it so that both sites can accurately point to the content that is found in search engines via one or the other but still end up in the right place. IE.,
http://utahautoscene.com/utah-auto-scene-is-coming-soon/
and
http://utahautozine.com/utah-auto-scene-is-coming-soon/

Without having to create duplicate content and be penalized for it.

Sorry for the long post, just wanted to make sure my question is clear.

Thanks and I look forward to your replies and ideas.