Does the Skype application have to be running on the PC with the desktop manager?
Yes, you need to have your PC on and Skype application running
Are you using data for the call?
No, only SkypeOut units are used (not VoIP).
How does it work with GPRS data rates?
IM+ for Skype Software uses GPRS connection only for keeping online and for text messaging. Each message is about 0,5 kB.