A dumb router/modem question

[death__machine]

I always see that the routers out there in the market have ethernet ports.
So ethernet is the port where you connect cables then connect the cables to a router and then to another computer right?

I want to use wireless internet, so are those routers different from the normal routers such as this

The ADSL service that i get over here is through a normal telephone cable, like the ones used in dial-up modems. All the wireless routers that i see have ethernet interface and ports, but no ports for a telephone cable to go in. Can anyone tell me where i am confused.. Also a good wireless router which is cheap and has a decent speed.

I read the sticky but i stil dont get it. :$

Thanks guys