I have forum1.com with decent amount of traffic (8GB) and well-known to some search engines, including Yahoo. Now I want to create a site2.com because it has better name and redirect site1 to it. Of course this can be easily done by signing up with mydomain.com and redirect site1.com to site2.com/forums.

But my main question is, doing that the search engines will updated and remove site1.com from their site (putting site2.com instead). So what should I do without losing my placement in search engine? Paying for hosting just for index.html page with all keyword and meta thing, then put a note to let visitors to go to site2.com. Will that work in order to keep my site's placement? Please suggest the best solution for this. Thank you.