How to view headers
In Gmail
Open the email in concern
Click the down arrow next to Reply, at the top of the message pane
Select Show Original
A summary of the headers will appear in a new window.

In Hotmail
Login into your account
Select Inbox from the left-side menu
Right-click the message you'd like to view headers for and select View Message Source.
The full headers will appear in a new window.

In Yahoomail
Login into your account
Select Inbox from the left-side menu
Right-click the message you'd like to view headers for and select 'View raw message'.
The full headers will appear in a new window.

In Rediffmail
Login into your account
Select Inbox from the left-side menu
Open the message you want to see the header and select view header
The full headers will appear in a new window.

In Outlook
Login into your account
Select Inbox from the left-side menu
Open the message you want to see the header and click file tab
The full headers will appear in a new window.
