I got my WAMP installed on my windows 7 64bit. cURL is not working, but still I got it enabled from the WAMP tray.
I have also uncommented
PHP Startup: unable to load dynamic library 'c:/wamp/bin/php/php5.4.3/ext/php_curl.dll' - the application has failed to start because its side-by-side configuration is incorrect. Please see the application event log or use the command-lin sxstrace.exe tool for more detail."
Go to http://www.anindya.com/php-5-4-3-and-php-5-3-13-x64-64-bit-for-windows/ and download the cURL version that corresponds to your PHP version under "Fixed curl extensions:".
So if you have PHP 5.3.13, download "php_curl-5.3.13-VC9-x64.zip". Try the "VC" version first. Then replace the php_curl.dll in ext folder. This worked for me.