Another question about a new domain name

Hello,

I really need help with this!


I'm running a VBulletin forum since February 2006: www elforro com ar

I have over 300,000 pages indexed in Google, and 4/10 PageRank. Currently about 30,000 visits from Google each day.

The thing is that I'm buying the domain www elforro com [without the .ar from "Argentina"] and I would like to know what should I do...

Should I set up a 301 redirect in the .htaccess from "elforro.com.ar" to "elforro.com"? And in that case, HOW?

I think I should also change the "preferred domain name" on Google Sitemaps, and change my backlinks wherever I can...

But I would like to know how to deal with redirects and that stuff in order to mantain my traffic [i would like to redirect "elforro.com.ar/something/" to "elforro.com/something/" for ex] and PageRank

Thanks in advance!

Edit: I'm doing well with this domain, but someday I would have to change it to ".com", so I rather do that now and not later. That is why I want to know the best alternative to do that. Also, the .COM domain is FIVE years old. Maybe this would help me too. Although the .COM PageRank is 3/10.