Fring Fring

For those of you who are using a Nokia phone based on the S60 Symbian OS, you might want to check out this software called Fring http://www.fring.com/

It allows you to use the GSM/3G network or WiFi to connect to Skype, MSN, Yahoo and even make phone calls using SIP.

Also available for Windows Mobile and certain Sony Ericsson phones.