I have been playing around with fring (www.fring.com) recently and I can't stop raving about it. Fring is one of the new generation mobile application making use of 3g and the cheaper data versus voice rates.
Fring enables you to make calls to your skype,google talk,msn buddies and sip phones from your cell. You can place voice call or use text based chatting using fring's im client. This has immediate benefits for us as often our consultants are out at clients whose firewalls and corporate policies block the im ports. So we usually have to make expensive cell calls to check on status and sort out technical issues etc. Now its cheaper to use the fring chat clients and if we need to talk place the call over skype or fring cell-to-cell.
Also you can now always be on the Internet, at least from your im providers point of view. With fring you setup your skype/google talk accounts and whenever your phone is one you are on the net and can receive communication as usual. Neat huh?
When I get time I will setup the office sip extensions on fring and then consultants should be able to call the office directly without having to use skype, google talk etc. Even better from the office should be able to dial a consultants extension to call them. This will be neat for transferring client's call etc without having to ask them to phone the consultant directly.
Fring will probably be more effective than icasa at reducing our phone bills!