Massive speed tip: Connect to your ISP without using their software.
Yes, this works on any dialup ISP, including AOL.
Find the program called DialGuard, and run it. Then connect to your ISP normally. DialGuard will popup and show the number that your modem wants to dial, and show your encrypted username and password.
What happens is, you enter your name and pass normally, and your ISPs software encrypts them and sends them to the remote server where they are verified.
Now that you have the encrypted version, go into your network places and make a new dialup connection. Add the phone number you normally dial, then put in the encrypted name and pass DialGuard gave you.
This trick even works with free ISPs... my parents have been using Juno's free internet access without using their software for 5 months now. They can stay on as long as they want and don't get disconnected (because there is no software running on their PC that can drop the connection from their end).
I used that trick for the three months before I got cable, and I almost doubled my speed (from 3k a second to about 6k a second, which is 2x faster).
Speed also depends on the quality of your phone line, and the type of modem you have. A standalone external modem will generally connect at a higher BPS than an internal WinModem (eww).