I noticed the php install directions mentioned that HTTP_Request2 was required, but I also wanted to note a couple options need to be compiled in (unless I missed them in the docs):
OpenSSL ( --with-openssl)
MB String ( --enable-mbstring)
HTTP_Request2 ( `pear install HTTP_Request-0.5.2` (it's alpha, so specifically mention the latest rev to override the download since it's not stable))
With the above setup, I'm not able to run the included samples ;)