I want my wordpress blog to be installed on a different (free) server. So my main site is at <domain.com> I want the blog to show domain.com/blog, is it possible.
To install wordpress in a different (free) server You need a MySQL user and database. So be clear that you have crated an MySQL database and User for installation.
With most free blogs your address will just be off of their domian until you set up your own hosting with your own domain. You will be better off paying for hosting if you can, when you set up your own WP files and SQL database they need a good environment to run well.
I'll clarify this. On my dreamhost hosting I have my main website. On a free server WHICH SUPPORTS PHP AND mySQL, I have my blog installed. I just want to tweak the .htaccess file to acheive what I said in the opening post.