301 redirects as jacquesm siad. That will take care of the search engines, anyway, which is probably where most of your traffic is coming from.<p>That said - you should also be analyzing your logs or whatnot to see where your traffic is really coming from, and more importantly,whether this new strategy is working before you shut off the old domain.
301 redirects. Follow jacquesm's link to Google's recommendation.<p>Here is my how-to guide on implementing what Google recommends:
<a href="http://www.joshklein.net/seo-basics-how-to-safely-move-redesign-your-website" rel="nofollow">http://www.joshklein.net/seo-basics-how-to-safely-move-redes...</a>