I am not an expert on this but i have been told you need a portable tape player thus,
http://www.amazon.co....eativeASIN=B00019MLF2
Then you need an appropriate twin jack-plug cable that connects from the ear phone socket on the player to the audio inlet of your PC. this can be obtained from a store such as Maplins.
You will also need to down load this free programme onto your computer, get the volume correct and off you go.
http://audacity.sourceforge.net/
Perhaps before you purchase these items, I suggest you ask again on this site, telling them that you have the aforementioned items but you want to know how to use them.