I want to ask how can one view the headers of the e-mails at
1. e-mail recieved in client software
2. e-mail recieved on web
If you're running outlook express for windows and microsoft outlook then go to inbox or wherever message is you want to check. Simply, right click on the email and go to properties it will display the true email address of the sender.

If you want to know a website that analyzes and reads email headers for you then go to www.spamcop.com and simply,
PASTE FULL SPAM HEADERS AND BODY OF E-MAIL
, and click Interrogate.