This should probably go in Internet/Networking.
As for your Outlook problem, you have to push your send/receive button b/c you have to set a preference in OE to go get email automatically. In Entourage, it's under the 'Schedules' option in the 'Tools' menu. Look for something like that in OE.
Secondly, Earthlink DSL does work with OS X. You have to configure the PPPoE tab in your networking control panel for OS X to make a connection to Earthlink. Enter the same account info you have to use in your PPPoE software and OS X should provide the same feature as that software.