Mick,
My wife and I recently got our Spouse Visa approved. We submitted Skype screen shots as well as email, YM and Facebook screenshots. These were all submitted as screen shots that I printed off. For Skype I took a screenshot of the Skype Window (the window you use for calling) with calls, duration etc. I submitted three separate screenshots over different time periods. The Facebook screenshots showed photos of our wedding and various visits to a few different places and included pictures with my family when they were across in the Philippines for the wedding. Email I just screenshot my inbox with the list of mails that had been sent to my wife over a couple of separate time periods.
You don't need to go too overboard, a few screenshots from each should be fine.
Hope this helps
Steve