htaccess Question

I have a Wordpress blog on a site that has hardcoded links with the
complete url.

I have replicated this onto a mobile subdomain.

The problem is that when reading the blog from mobile.some-site.com all
the links point to www.some-site.com. I'd like to rewrite these to
mobile.some-site.com

I can't quite wrap my mind around how to do this. I haven't been able to
do it with HTTP_HOST.

Jeff