Call Forwarding is configured using the options in the Skype client. The instructions are quite clear on how to forward calls to a telephone number.
It's not immediately obvious, but you can forward calls to other Skype usernames, not just to telephone numbers.
Here's an example to forward calls to a user called MyOtherSkypeAccount,
Go to Tools | Options | Calls | Call Forwarding
If you see a warning about Skype Credit, just select "Call forwarding options" to reveal the options.
Check the box marked Forward calls when I'm not on Skype
Now type a Skype username in the box marked Enter phone number
In this example you would type MyOtherSkypeAccount in the box.
Click SAVE to store the new settings.
In the example above, if someone calls when you are not on Skype then the call will be forwarded to MyOtherSkypeAccount.
2007-06