Subdomain for posts only? rewriterule htaccess?

Hi guys,

I’ve just moved over from blogger. Whilst I also had (and have) my own URL (www.mywebsite.com), the blogger page pointed to a subdomain, blog.mywebsite.com (using CNAME or something)

I’m having a really hard time trying to maintain my old URL structure in the new wordpress site. Now, of course, all of this is contained in http://www.website.com/wordpress

I’ve set up the wordpress to work from the root folder (so the pages are good), but the subdomain (where I want the posts) is giving me a massive headache!

So, how can I set up a subdomain blog.mywebsite.com which shows the wordpress posts?

Help would be greatly appreciated, I’ve been at this for days!