mystique, here is the nitty-gritty. Since the pages are not just HTML, that is, they are PHP that outputs HTML, the only way for you to get the source files is ftp. If they were simple HTML pages, you could just view source in your browser and save them. I assume your site is data-driven, so PHP was a good development option.
Did either the guy hosting the site or the programmer give you an "ftp username and password"? If so, then ASAP login to your webserver using your ftp account and download all the files (including images, etc.) to your local harddrive.
If you have data stored in a database (such as MySql), do you have any access to the data that would allow you to export to text files or some other format? (For example, do you have access to something called "phpMyAdmin"?)
If you don't have access to the source files (ftp account), and you don't have access to get your data, then you are absolutely at the mercy of these guys. Of course you could use legal force, but will this be more trouble than it's worth?
If you don't have this access, and you ask them for it, they will immediately suspect you are up to something, and they'll make it even harder for you--most likely.
Now, in defense of the programmer, I understand where he's coming from to an extent. If the pages are 90% PHP code, and especially if he uses PHP to print out most of the HTML, then a non-programmer is very likely to mess up the code trying to edit the content. Now, if he had planned to build the site in a fashion where you could edit it from the start, he could have done that, but it would have been more work for him. I have plenty of data-driven sites I've built for clients where part of the deal is a controlpanel that allows them to change the parts they want.
If the relationship is going sour, and you end up needing a new host and/or PHP programmer, please contact me. Obviously, the best thing would be that you are able to work with you current people without getting gouged on the money.