If I purchase an ADSL router do I need an ADSL Modem as well or does the router alow me to get on-line by itself?

you need a adsl modem either way. use a router with it if you want to share your connection to several computers in your house

Extracted from Nokia FAQ Pages Modem vs Router Until now, the device most of us used to connect to the internet was known as a modem. A modem is a relatively simple device which acts as an interface to the telephone network for a single PC. The connection to the internet itself is made by software running on the PC (often part of the operating system itself). The equivalent for ADSL is a NIC (Network Interface Card) such as the Ni200. This acts as the interface to an ADSL network for a single PC, again the actual connection to the internet is managed by software running on that PC. ADSL modems require specific software running on the PC to function - for this reason not all PC operating systems are suitable. By comparison, a router is a true "stand-alone" networking device, designed to route data for a number of PCs to and from the internet, using its own ADSL interface. The Nokia M1122, MW1122 and Ni500 are all ADSL routers. An ADSL router manages the connection to the internet itself, removing the need for special software on the PCs. Most devices with an Ethernet (and/or wireless LAN in the case of the MW1122) interface can be connected to the internet using an ADSL router. Because routers are inherently more flexible and complex than modems, it sometimes necessary to configure them to operate correctly in some situations.