WordPress 3.0: Changing to new post types

Hello,
Having custom post types in the comming version of WordPress 3.0 is a superb addition. I’ve been trying a few things with the latset RC and was curious if it was possible to change a standard post into a new custom post type.

For example i have a portfolio section with 45+ posts, i want these to go under a new post type called portfolio. Is it a case of re-adding these posts to the custom post type and removing the old (i hope not).

Thanks in advance!
Matt