This is a great piece of kit, once you get it installed. As other people have said, the instruction manual leaves a lot to be desired.
Here are my installation suggestions. I have Windows XP and Skype 4.
First install Skype, if you haven't already got it and check it is working.
Next connect the phone and landline to the Sogatel Adapter and then connect the Adapter to your USB. When asked allow Windows to automatically configure the Adaptor.
Now go to the Download section of the Sogatel Website and download, install, and run Skypemate. When Skype asks click to allow Sypemate to use it.
Your phone should now work with both landline and Skype.
It is very important that you don't install Skypemate until after Windows has configured the Adapter otherwise you will have problems.
The Speedial system described in the Instruction manual as the way to contact other PC users is not available in Skype 4. However, it is still possible to initiate the call from your PC and then have the conversation via the phone.
I have seen suggestions that reverting to Skype 3.8 solves this problem, but I have not tried it.
Skype calls are only available when your PC is on, however, the landline continues to work normally even when the Adapter is off.
Overall I am very pleased and would have given the product 5 stars if the instruction manual had been up to scratch.