You found us out EW! Not only have we made it incompatible with AOL, we are working hard to make it incompatible with Microsoft products - You'll have to use OS X, UNIX or LINUX
ISP - is your I
That which provides you with a connection to the Internet.
Earthlink is not a bad choice - in fact it has the only toll free phone number I can use in my location which is the main reason I use it.
You can keep AOL and still use a different ISP to dial in (or cable in or DSL in). I keep an AOL account to test the website in their browser.