C# .NET - login in yahoo and gmail

Hi,

I am making the project as coding in c# and designing in silverlight3

I'd like to make an application which can help me directly log in my
Yahoo!mail or Gmail account without typing user name and password.
Basically, I want to set up a link, click it and pop up the Yahoo/Gmail
page.

so that user will not have to type their username and password again and again...

help me

Not possible because u always need different user cridential (userid/password) for specific site yahoo , gamil etc.

direct login is possible only when the site provide any way to share user cridential for authenication & authorisation then u will be able to do that thing in  your application. otherwise when u redirect to that site always need to userid/pwd

You can hard code the account credentials and replicate the behavior of a desktop email client (like Outlook) to send & fetch emails with a custom interface.

Simple Mail Transfer Protocol (SMTP) server handles the sending of your email messages to the Internet while a Post Office Protocol 3 (POP3) server holds incoming email messages until you check your email. You will need the Yahoo & Gmail SMTP & POP3 account credentials

This link shows how you can send mail programmatically using GMail - http://mvark.blogspot.com/2006/09/sending-mail-programmatically-using-c.html

You can retrieve Mails from Gmail & Yahoo with POP3 using the open source library Indy.Sockets:
http://www.codeproject.com/KB/IP/POP3ClientByChadZHower.aspx
http://www.indyproject.org/

Before you fetch mails from Gmail, you will have to enable POP access explicitly - http://mail.google.com/support/bin/answer.py?hl=en&answer=13273

These are the details to use:
pop.gmail.com

  Use SSL: Yes

  Port: 995

Your Yahoo Mail account POP3 & SMTP server details may vary according to which country/region you belong to.

In your Yahoo Mail account, under Mail Options, click on POP Access and Forwarding and the precise Server Settings will be listed under POP
Access Settings. For an India-based Yahoo Mail account (ending with ".in") the details are:
Incoming Mail Server (POP3):        in.pop.mail.yahoo.com
Use SSL, port: 995

Outgoing Mail Server (SMTP):     in.smtp.mail.yahoo.com
Use SSL, port: 465, use authentication

Gmail provides free POP access -
http://mail.google.com/support/bin/answer.py?hl=en&answer=10350
http://mail.google.com/support/bin/answer.py?hl=en&answer=13273