While it's free to make calls between computers running Skype, you still have to pay to make calls to a traditional landline (or mobile phone). To make calls to a conventional line, you need to purchase credits (known as SkypeOut) from Skype. Check out the Skype rates. In a nutshell, the rates to make calls using SkypeOut depend on where you are placing the call to, not where you are calling from.
While SkypeOut allows you to make calls to a conventional line, the reverse can also be achieved using SkypeIn. Using SkypeIn, a person using an ordinary phone can call your Skype account on your computer. SkypeIn assigns you a phone number where callers can reach you. For more information on SkypeIn, check out the SkypeIn page.
Skype Voicemail comes free with SkypeIn and lets you send and receive voice mail on your computer. Using Skype Voicemail, you can record voice mail to send, or listen to voice mails that callers left while you were away. Get more information on the Skype Voicemail page.
Besides voice calls, you can use Skype as an instant messenger. Figure 12 depicts two people chatting with each other. You can also invite more users to join the chat by clicking on the yellow "Add more users to this chat" button.
Figure 12. Chatting using Skype
Skype also supports file exchanges (see Figure 13). This is a good utility for the quick transfer of files from one person to another. (It works great if you have multiple computers at home or in the office too! To send files to another person, simply right-click on the contact name and select Send File.
Figure 13. Sending a file to another user
One of the strengths of Skype is its multiple-party voice conferencing. Using Skype, you can have up to a five-way conferencing call. Note that one of the conferencing participants must be the host, and only the host can invite participants to the conferencing. More importantly, the host should be the one with the best internet connection.
To invite someone to a conference, click on the name of the contact and select Invite to Conference (see Figure 14).
Figure 14. Inviting someone to a voice conference
Participants will be able to see who is in the conference (see Figure 15). I have tried a four-way conference, and the sound quality was very impressive.
Figure 15. Viewing the participants of the conference