Migrate posts of certain category to CustomPress custom post type

I have some posts in my site that have the basic information (title and content) but are not part of the regular blog entries (such as portafolio items).

My current theme sorts out which are portafolio and which are regular entries based on category in order to hide the portafolio items from blog post list.

However, I have kind of grown tired of my current theme and want to change to another but have not been able to since other themes do not work as this one (and portafolio and posts end all mixed up).

I have really become fond of CustomPress and am currently thinking in migrating the portafolio post to a custom post type, and thus becoming independent of the theme.

Since there are more than a few post in the portafolio category, I wondered if there was an easy way (or a way at all) to make all the posts in the portafolio category part of a new custom post type named portafolio.

Thanks in advance :smiley:.