Gmail
http://aspdotnet-suresh.blogspot.com/2010/04/import-contacts-from-gmail.html
http://www.netrostar.com/Tutorials-210-How%20to%20import%20address%20book%20from%20Gmail%20using%20C
http://code.google.com/apis/contacts/docs/2.0/developers_guide_dotnet.html#Retrieving
yahoo
http://developer.yahoo.com/dotnet/howto-rest_cs.html
Yahoo/gmail/hotmail address book at below link
http://sourceforge.net/project/downloading.php?group_id=210092&filesize=178426&filename=OpenContactsNet-1.0.zip
http://aspdotnet-suresh.blogspot.com/2010/04/import-contacts-from-gmail.html
http://www.netrostar.com/Tutorials-210-How%20to%20import%20address%20book%20from%20Gmail%20using%20C
http://code.google.com/apis/contacts/docs/2.0/developers_guide_dotnet.html#Retrieving
yahoo
http://developer.yahoo.com/dotnet/howto-rest_cs.html
Yahoo/gmail/hotmail address book at below link
http://sourceforge.net/project/downloading.php?group_id=210092&filesize=178426&filename=OpenContactsNet-1.0.zip