I wrote a PHP library for the API which uses non-blocking/asynchronous requests. It's up on github. Contributions welcome :).
http://github.com/jmathai/epicode/commit/556f8eaeefa217d080d4734d0c3a838c59cd6eab Blog post with an example. http://www.jaisenmathai.com/blog/2009/03/31/how-to-quickly-integrate-with-twitters-oauth-api-using-php/
