Yep, there's R plugins to do it, or you can build it using Groovy script, or you can use RapidMiner directly.
I did build the Twitter API in RapidMiner for a previous company using OAuth, (sadly I don't have all the code these days, but use OAuth pretty regularly for other services) it's actually really straightforward.
Here's a link to a forum post with a sample process using the authentication: http://rapid-i.com/rapidforum/index.php/topic,7149.msg
The basic idea is create your login credentials, pass this credential into a macro, put this in the header of your request to the service, receive your login token, read this login token (XML) and pass it into a macro, use the 'token macro' in the header of your requests.
One this to look out for is that the API only returns a set number of records so you'll need to use another macro inside the body of your request alongside Loop Until to ensure that you get all the data you want.
Hope that helps.