If they have borrowed your address to use for a return address of their junk you are too late to do anything about it now. They will get bored with you soon and move on to the next donor.

Just be protective with your personal info including your email address. Do not post it in public forums. Do not sign up for every free offer that you see on the Internet. Our personal info gets out there enough on its own without our help.

This article explains backscatter. http://en.wikipedia.org/wiki/Backscatter_%28email%29

In other words, grin and bare it, eh?

It would be useful for any of your contacts to know an email really is from you.

One method would be to create a html signature and use it when you send emails to your family and friends.

They may have already received some of those 'bogus' emails, so perhaps it might be a good idea to send them an email appologising if they received any bogus emails allegedly from you. Inform them that in future they can tell if the email is from you if it has the specific signature as shown in the email.