You can reach YaST2 from the menu. There will be several modules on the left hand pane. Select "Network Devices". A shortcut if you use KDE is to press ALT-F2, and enter "kdesu yast2 network" in the run box. This is start with the networking setup dialog. Select your device in the upper right-hand pane and click edit. If you choose "Auto" configuration, it will use DHCP which will set your IP, Netmask and Gateway settings automatically when you boot up.
Is your ADSL modem a modem, or a Modem with a built in NAT router? Or do you have a NAT router? You mentioned that you have Windows hosts. If you can use them at the same time, you probably have a NAT router.
SuSE has a DSL configuration tool, but if you have a NAT router, you don't need to use it. The dailing is done by the router.
Make sure you change the HOSTNAME of your computer, if it "localhost" presently. I don't think a fresh SuSE install does that, but some distro's do.