One option might be to set up a blog for the new domain and use it more as info rather then a marketing tool at first. Once it gains popularity, popularity being inbound links from social sites, yahoo, and others. after you have many posts, and other inbounds then link it to your site as an inbound link. might even consider putting the new domain on a different IP for more optimum results. In fact the more link bait the better. So why not 2 blogs 3,4,5 as long as they are all different, informative and not spammy.
Google loves blogs, put social bookmarks on em, rss's will get picked up and away you go.

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Tony V Get Paid To Blog Even If you don't Blog