Have been using SKype recently, and am finding myself getting more and more into it.
This app (found at www.skype.com) provides VoIP, Instant Messaging and File Transfer. The IM side is pretty standard (although at least I don’t have to go thru the whole Passport signup that MSN insists on!), but its the VoIP thats the most exciting.
I’ve had conversations with coworkers (in the same city) which sound better than a mobile phone (I’m using a $19.95 headset/mike from Dick Smith). And tonight I got a call from a mate in Ireland (I’m in Oz) which sounded as good (and equivalent lag) to a normal land line call. We chatted for 30 minutes, and during the conversation swapped photos. Total cost – $0.00.
Well worth a look if you haven’t already. The more tech oriented will find a whole SDK available for people who want to leverage off the platform, and they offer a paid service which allows bridging between normal phones and Skype.