We have a good session covering this on Monday June 23 in Santa Clara, attend if you can!
Otherwise will try to publish details on how you can do this soon. There is some code in the docs that talks to Amazon Alexia service, that is a good start for talking to a REST service.
Look at the Apex Language Reference under Invoking an external service - it tells you how to generate the client side stubs to consume a SOAP service. There is also a google toolkit & doc on how to use GData APIs from Google
BTW, you can't use an arbitary transport protocol to communicate with an external service
Otherwise will try to publish details on how you can do this soon. There is some code in the docs that talks to Amazon Alexia service, that is a good start for talking to a REST service.