I followed some advice I was given to identify the cause of my inability to connect to my ADSL router using an ethernet cable. I spoke to a couple people about it (thanks Rich and Andre amoung others). I eventually took my PowerBook to the Apple store I bought it from and it turned out I had a faulty ethernet port/board/thingy on my PowerBook. Thankfully my wi-fi, Bluetooth and dial-up connectivity options still work and the nice people at Cool Apple Buddy are going to sort this out for me next week.
In what can only be described as suspicious timing, my PC started refusing to turn on this morning so, left with the unhappy option of no meaningful internet connection until my PowerBook is sorted out, I bought an AirExpress (you are absolutely right Rich, it rocks!). Loads of money later I am connected and doing stuff. Now if only my tech guy can get my PC back on I can start trying to figure out how to move my Outlook contacts and data across to Entourage.