checking all email at one place.

Question

hello to all 

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

There is an option of E-mail in my project

It has 5  parts

1.) Inbox

2.) adress book

3.) Drafts

4.) Templates

5.) Settings

Now almost all points are completed except the first point i.e "INBOX"

user have there  e-mail id at gmail,hotmail,yahoomail e.t.c

Now I want user the facility to check all e-mails of different-2 e-mail id's  in my project..

I want to open all Inboxes in my own application..

How it will be possible...

Thanks in advance