Only by running your own mail or news server can you prevent the ISP from monitoring your email or news reading.
Sorry to entering this thread so late but I had to bite on these comments. I have been in and out of the ISP business for the last 5 years. In my last real job I was responsible for a tech support team. Tech support personnel in ISPs are typically an entry level position with only slightly better starting wages. I couldn't get most of the techs to read what I wanted them to read and I would be surprised if any of them did any snooping.
I fired 2 of my original 8 staff members for browsing the mailbox of users. I Know several people who work in both the Big national ISP and the small mom and pop ISP at a tech level, to a CEO level. I KNOW that, security notwithstanding, email browsing across the server isn't that uncommon of an occurrence. Ian Briggs