There is no easy way (especially if you don't have access to modify your php.ini file). It's best to just rename them, and your links to *.php files.
Secondly, if you want to code in PHP, find yourself a good PHP IDE, and dump the WYSIWYG editors (especially Front Page). Coding in PHP is not glamorous, and is mind boggling sometimes, when you look at all the code, but well worth it to learn.
Renaming your links shouldn't be that hard. Heck, even Notepad has a Find function in it... Yeah, it may seem like a lot of work, but it is well worth it in the end.
If you don't want to rename everything, then consider Server Side Includes (SSI) as an alternative to php if all you are planning is just to include a bunch of files anyhow. But, even with that, you may have to rename your files to *.shtml (depending on your webhost's configuration).