club project I'm working on with English classes in Argentina.
Step 1: Gmail Contacts
First and foremost, make sure everyone has a Gmail account, and make sure their Gmail accounts have the appropriate permissions (school accounts may block things like Google + or YouTube, and that could foil the whole plan).
I suggest collecting classes--both yours, and those with whom your classes are communicating--in their own Contact List groups then exporting the groups (just the groups, not your whole list) as a CSV file. I also copy just the emails separately to a document so I can have a list of emails with nothing else but commas separating them. Trust me, this will be useful.
Step 2: Blogger
Set up a blog on Blogger.com* for the interaction and go to Settings. Copy your list you have already copied, pasted, and whittled down to nothing but emails and commas into the "Add authors" section. If your students are like my students, you may have to do this a few times to make sure they both open and accept the invitation to join. Once they have joined, they can create a new post on the blog that everyone now shares, and anyone can see who posts what when, and of course they can comment on each other's posts too.
Generating a list of labels (tags) you want them to use on an introductory post that you add can help facilitate specific post location down the road. Since we're collaborating with an English class, I made a separate page to list the English class's topics and one for our Spanish class topics, plus a page of directions on how to contribute and now one where a calendar of class-time appointments (Google Calendar is another great feature--though it doesn't really involve actual interpersonal TL communication) can be set.
Step 3: Google Plus
Google + is free with the Google account, but it must be activated to use many of the features that follow. You could use the Circles option here to organize student contacts as well, especially if they're working in certain groups for a period of time and you need to be able to contact individual groups separately.
Step 4: Google Communities
Create a community--preferably with a theme that will promote discussion beyond listing a few favorites. Link to the blog and copy and paste your e-mail/comma list of students to invite. I've made my community private, but people can search it and request to join. If students haven't activated Google + yet, you may need to just "share" the community with them as kind of a hint so they can request membership once they have joined.
You can also set up separate post categories. For my purposes, I went ahead and made a separate category for each club topic. In time, this may replace the blog, as students can post text, photos, videos, links, and even events, which could be topic-related occurrences in the news or just plans to meet up and talk! They can even schedule Hangout sessions and get reminders, but I'm getting ahead of myself.
Step 5: YouTube*
Make sure that your account at least is connected to YouTube, proper permissions in order, etc. If nothing else, you will be able to record this way. Anyone else who wants to record Hangout conversations will have to either make sure their account is connected or that they're grouped with someone whose is and that that person initiates the Hangouts.
Step 6: Hangouts/Hangouts on Air
With just the Hangouts option on the right of the Google + page, anyone can start a chat or video call with any of their contacts, even their circles if they've arranged them by, say, clubs. They can see all participants in real time and even share their screens or simply chat.
However the really cool thing that could solve a lot of problems for me, especially reflection and collecting evidence for e-portfolios, is the option on the left for Hangouts on Air. Kids can, of course, copy and paste Hangout chats if they just need interpersonal evidence, or even start Audacity as soon as their conversation starts for a simple audio file. However, starting a conversation with Hangouts on Air rather than simply Hangouts means you can record video.
CAUTION: Hangouts on Air conversations are automatically sent to the YouTube channel of the person who started the conversation--live and recorded, so there may be some privacy issues that you need to work out with your district and/or students. One way to address this could be disabling video an just showing the avatar when they are speaking so they can still record screen sharing, for example. Alternatively, students could download the conversations quickly and remove them from their channels, perhaps.
Community can be one of the hardest of the ACTFL's 5 C's to address, and establishing genuine contexts for target language interactions beyond the classroom is no mean feat. However, with these tools from Google, we can bring the rest of the world a few steps closer to our students, at school and at home.
BONUS: (from @mjmergen) Have students click the little microphone on Google image search and ask a question in TL about basic country facts (e.g. capital, president, flag, map), and the search will pop up with visual responses to the question! HINT: they may have to repeat the search a few times to get the question to come up right--"quien" was especially tough even for me.
They can do PrtSc screenshots to send to you to show 1) that Google understood them and 2) they obtained the desired information!
Special thanks to @EricSims528 and @JaymeLinton for introducing me to some of the secrets of Hangouts!
*affiliated with Google, of course