C'mon people.... this isn't rocket science.
You connect an Amiga to a network the same way you do any other machine. (And I should know... I have two Windows machines, a linux boxen, a TiVo, an SGI, and two Amigas on mine... I am thinking about somehow getting a C64 on too, but that's for another post.)
Anyhow, it sounds like you have it figured out, Jump2b....
You need connectivity (TCP/IP) before any clients (SaMBa, FTP, etc) will work.
For that, you hook the ADSL into the uplink on the router, and then the PC and Amiga into the regular ports on the router. Make sure you have the router configured properly (most easily done from the PC by following the instructions that come with the router) and the Amiga can most likely use DHCP (from Miami, Genesis, or whatever TCP/IP package you use), and be done.
Once you get the PC on-line and able to surf the internet, you'll know your ADSL and router are working right. Then get the Amiga to go out and hit the internet. Then you'll know that the router, Amiga, and PC all have valid IP setups. This is 3/4ths of the battle. The PC and Amiga should also be able to "ping" each other here. (You may choose to test this to make sure, but I haven't seen a time when this wasn't the case.)
Once you know the physical networking is in place, then you can mess around with one of the many on-line Samba tutorials, or say "screw this" and just transfer files over FTP or any other IP-based protocol. Personally, I haven't had great luck with Samba on the Amiga, and I simply run an FTP daemon on my Linux box, and AmiFTP from the Amiga to send and recieve through FTP. Samba on the linux box maps well to Windows XP and Windows 2000 shares, though, so it is possible, I just haven't messed with it enough.