e-mail contacts

[#1]

Do I have to inform all my contacts that I have changed my e-mail name and address?
Or is this done automatically

[#2]

If you mean your actual e-mail address as opposed to postal address then that would be a good idea.

[#3]

Tinkytoo
I depends on your interest in technical matters, but you need not close your old account, depending on the previous ISP your e-mails could be forwards for months or even years after leaving your previous ISP. Giving you the comfort of not loosing contacts.
see this thread
http://community.plus.net/forum/index.php/topic,99758.0.html