In Mandrake it's quite easy when using Mandrake Control Center.
The method of configuration depends on the connection you use.
For dialup you need a driver for your modem (can be with your system, but may be not, so you may need to search for it in the Net). When the driver is installed, use one of the diallers (like kppp) and set up your account.
DSL with non-static address: you need to configure DHCP-client side (maybe something more, it depends on the provider, I don't use AOL so I don't know). For more info, please look there: http://www.tldp.org/HOWTO/DSL-HOWTO/index.html
Static connection: depends on the connection.