PPPoE is for connecting to DSL like services that require a username/password.
DHCP is for connecting to always on services like cable.
Some DSL modems have the username and password stored in them and connect to the net on their own. Disabling that feature on the modem and having your router handle it can increase your speed..
Just incase that didnt make sense, look at it like this. Your connecting to the net with your modem and your router is connecting you to your modem. Its like going through two routers to get to the internet. Making the router place the PPPoE connection will make things faster because your packets arent going through two routers to reach the net.
If you have a cable service, leave it DHCP. Thats the right setting.
