I want to import one blog to another, but have that constantly happening, i.e. when I blog on one site I want it to appear on the other.
Take a look at the FeedWordPress plugin, I've used this on one client site to aggregate feeds from their other sites and republish the latest post from each site. The UI is a bit complex and unfriendly, but it does the job.
a trick would be to blog by email
set up both sites to publish thru the same email.
once you send email - it is auto published to both at same time without waiting for cron job of aggregation to happen