[gmmour]

In order to help you, I started to register my Cosmokarta with the my account system so I'm still waiting for the confirmation SMS and I'll give you the first steps here:
First you go to cosmote.gr and click on the my account icon on the top right side of the site. Then click the second radio button that says "COSMOKAPTA/WHAT'S UP" next to the greek gibberish.
Then, click the first option (it's selected by default) which means you'll sign up using your user password (a five digit password printed on the plastic folding of your sim card next to the greek text "ΚΩΔΙΚΟΣ ΧΡΗΣΤΗ" (KODIKOS XPHSTH, meaning "user code"). On the next page you have five textboxes, you fill them as follows: username, email address, 10-digit cosmote phone number and 5-digit user code, then click either e-mail or SMS to receive your password by email or SMS! (If you're not in Greece and can't receive sms on your cosmokarta, choose email).
After they validate your data they will send you your password by email or sms (depending on what you choose on this page)!

I'm still waiting for mine!

If you don't have the 5-digit user code, then you can't sign up for "My account" through the website...

I'll get back to you as soon as I get my password for the rest of the steps you need to take to sign up for WEB'n'MAIL...