So someone is e-mailing you and it's pissing you off. The reason you came here is because your sick of it and you want to get to them, am I right?
So really having their ip isn't enough, is it? You want to call them by their name, know their age, threaten to call their parents. and here's how:
Firstly I have to stress this is nowhere near fool-proof (I'd say only 50% to start with), in fact, the further you want to go, the smaller the chance of success.
The solution is deceptively simple: social networking.
YES! Most people use one account for everything (or their public, and who would get into an internet argument with their private email?) so you can simply take the persons given email, log on to facebook, myspace and do a search for their email (google, likely or popular forums might help too). Tadaa. You may now have their name, which is a good start but that may not be all you want, yes? Their location is most likely posted, but if it isn't, the chances are most of their friends are from the same place, and their information may not be so private. Unfortunately a lot of juicy information may be private so at this point it's a bit harder.
The solution? Add them. Not with your account, silly, make something, it can be anything from "1000 friends in 1000 days!" to a made up, normal name.
If they're lax about friends, they may accept you, if they don't, don't worry, find one of their friends with the MOST friends as they will be the most relaxed and add them. This is to get the "friends only" information (facebook posts are often friends only and these can be great if they post what they're up to).
Knowing that information can be pretty unnerving to any so-called anonymous e-hater. The next, less-full-proof method gets personal. This is for when you are REALLY pissed.
IF you're in luck the person may have their parents added, if so, BRILLIANT! Internet phonebook time! And there you have address, phone number etc. If not you might want to do a search, try narrow it down using friends etc and try the phonebook search. If that fails, oh well, google might have something for you.
So remember, Google is your friend, and not every anonymous e-mailer is quite as anonymous as they think.
Don't let them get to you, it's probably a twelve year old and there is no way they can discover who you are, unless your an idiot.