You could try to capture the HTTP request when you are posting to a blog, and modify & resend it with cURL. The problem is, you also need to login to your blog etc through cURL. Doing these types of things is most of the time pretty hard.
http://curl.haxx.se/libcurl/php/examples/blogpost.html there is a blogger post example, so can we edit it?
waste of time ... just post by email. PHP can send that stuff very easily without curl. http://codex.wordpress.org/Blog_by_Email