cheap internet / cable

I have a question regarding my DSL that you might be able to help me with. We currently have our router in the upstairs of our house and it works fine, but when I get a 360, I am moving it downstairs to be near the system so I can plug in directly. To do this though, I will have to run a new phone line because there is only one phone jack in the downstairs and we already have it split between the phone and our DVR. Sooo… I was going to run a new phone line (just the standard cord with a clip on each end) down through the floor and into the basement which has a dropped ceiling and the to a phone jack in the laundry room which we don’t use. The cord might end up being a little long, will that be an issue? Will it slow down the connection?