Not all Web servers have cURL installed and compiled (as you're obviously aware, since there is an error handler built into the plugin that checks for cURL before anything is done). However, there is no reason to require cURL, since WordPress provides a sophisticated class to perform HTTP Requests.
I've modified the current trunk version of this plugin to remove the cURL requirement, replacing it with the use of the WP_Http class, instead. I've generated a patch with all of these changes and pasted the contents of that patch at http://pastebin.com/dLbKJHqp.
In my initial tests, it looks like everything is still working the way it should be, even on a server without cURL. I hope that helps. Thanks.