Another note to aol users---all of your mail keeps getting returned to me.  If you use AOL please take a moment to check your SPAM mail folder and update your settings.  Better yet, open a hotmail/yahoo account.  Its always better to use something ANONYMOUS.  AOL should be your last resort when contacting anything 'naughty' anyways.

even anonymous e-mail addresses have the sender's IP address buried in the header. For those with broadband Internet access, your IP address doesn't change very often.

If one concientiously uses a dialup modem, they are probably tougher to trace, but I doubt impossible.

as far as anonymity goes.  

You are right about IP addresses, but tracking that is so rare for LE.. I haven't seen it happen as far as this line of business goes...but LE HAS looked up clients name and address from AOL POSTERS.  Don't use aol for posting.  Just don't.  
Today, I don't think you need to worry about IP tracing, but you do need to ditch the AOL account.  AOL can and does give up your name and address to any law enforcement body that asks, and there does NOT need to be a court order.  AOL is like DISNEYLAND when it comes to your privacy, they err on the side of being PC  politically correct...
use a big boy system, not AOL.  anytime you have to pay for and insert your real name, its ..DUH..not anonymous.
But I'm sure 'surelyyoujest' could give you guys even better recommendations for what service to use  My vote is just 'anything but aol'  but a techy person can give you even more advice

which proved to lots of folks who didn't even have computers that AOL is for crap!

I recently realized I did not need AOL anymore as I have cable high speed. I called and cancelled after they would not let me off the phoen for 20 minutes.. LOL, and now I have to say my computer is running MUCH better and smoothly, NO THANKS aol and to think I paid for it for 4 years... auugghhh