I wanted to have only one .htaccess file for one site, but have it work differently in two different environments. (One being Apache 1.3, the other 2.0.)
By having a look at my Apache httpd.conf, I looked for a module that would most likely not be loaded on the remote host. In my case, I decided on mod_asapi.so. I then added the conditional statements like so:
# Turn on register_globals on local machine (turned on by default remotely) <IfModule isapi_module> php_flag register_globals 1 </IfModule>
If you wanted something which worked only on the other machine, you could just use the ! operator to negate the test.