Mobile VOIP client fring has just announced for the Windows Mobile platform, opening up support for SmartPhones and PocketPCs. This is an interesting way to essentially turn your mobile handset into a free VOIP client, provided you can get access to a free data connection.

fring lets you talk and IM using your data connection instead of your voice plan minutes. This is most useful if you have an unlimited data plan, or can connect to a Wi-Fi hotspot. Supported connections include Skype, MSN Messenger, GTalk, Twitter, and quite a bit of VOIP clients.