If the domain name is the same, and you are just moving the host and the platform, keep the URL structure the same and move the content over to the new site.

If the URLs are going to change, you should consider 301 redirect from the previous URL to the new one.

Its better you redirect all the url to new website.so not need to copy all article, it will same more time.

Rajeev gave you the correct solution... Google records content against URLs.. If you are not going to change link structure / content urls,, you don't need to worry... and if you are changing urls as well then you should use 301 on old pages/urls

If your domain is same than you have to no need for change the contenet

Ok domain you can stay as the same. You do not need to rewrite your content just use web aster tool to remove Uris.

Since domain is the same, you don't have to rewrite the articles.

Anyway the op is merely changing web host. What's this got anything to do with 301 redirect? O_o He's not changing domain.