Enabling the curl extension on my PHP IIS installation is simpler than I thought.
After some googling and finding some good posts (such as this one http://www.tonyspencer.com/mt/archives/2003/10/curl_with_php_a.htm), I realized that since I manually installed my PHP5.0 with the windows zip package I already have php_curl.dll in my php/ext directory. All I had to do to run curl is just two steps:
- uncomment the line that has extension=php_curl.dll
- restart IIS web server
You can use phpinfo() to verify before and after you enabled curl.
Btw, if you are relatively comfortable with IIS and web server in general, you should always use the manual installation of PHP (http://us2.php.net/downloads.php).