The shear size of the Skype global community and the large choice of free and paid add-ons to Skype makes it a top choice of VoIP services. SightSpeed may have a little better quality video quality and GizmoProject may behave a bit more like a traditional phone service. But Skype is still the 800 pound gorrilla in the jungle. I use it alot.
These are the basic key features of Skype:
From within Skype you can talk, IM or video-conference with any other Skype user worldwide for free. Call any landline or mobile phone for cheap rates. Landline phone rates start about 2.1 cents a minute for most called countries. Mobile rates can be a bit trickier because of the number of mobile phone companies and how they charge. However; there is a rate page at the Skype website with rates worldwide. For instance, Singapore is 2.1 cents a minute whether calling a landline or mobile from the USA.
Skype can conference up to 5 people in a call on any computer and up to 10 people in one call if the people on the call are using a PC with an Intel Duo Core Processor.
You can purchase a Skype phone number (approximately $30 per year) to allow people without Skype the convenience to call you. You can choose a SkypeIn phone number with the area code of your choice. If most of your customers or friends are in a different geographic location (state or country), get a number thats local to them to save them a toll call.
You can also set up Skype Voicemail so people can leave you messages when you’re not around.
Other free Skype features:
Global User Directory
Call Forward up to three other Skype IDs.
Instant Message (same as chat)
Include groups of up to 50 in one chat.
File transfer - Instantly send and receive those big, hard-to-send files safely.
Call logs - Keeps track of both calls and chats.
Mobility - Log into Skype from anywhere in the world.
Skype has different rate call plans for calls outside the Skype network such as: SkypePro, SkypeUnlimited and Skype To Go, so it can get a little confusing. But, the cost savings make it worth the effort to research them.
Some interesting and informative Skype links: - Skype Forums