The X-Series package gives you unlimited web access for applications like Skype, Yahoo! search, Windows Live Messenger. It makes using the Internet on a mobile a viable proposition. Also, because it’s a 3G handset, data applications are reasonably fast.
The handset also supports WiFi so you can make VoIP calls via a wireless router at home or via certain wireless hotspots out and about.
The handset uses the Nokia Series 60 operating system so there are lots of applications available. S60 is a good place to start.