I have hosted a minecraft server for my friend and I and lately my internet speed dropped quite a bit.  It may or may not be related but Iknow Comcast likes to throttle you if you upload too much.
 
That said how much upload would a minecraft server use for a few hours each day over two days with the local host and one user connected?

i myself have never actually monitored how much minecraft uses, but i run many services on my home network and people still game fine on a 768k upload.  I'll see what i can't figure up for ya though.

alright well i didn't do anything fancy to test, i just logged into my server no one else was connected at the time, but it averaged about 200-250kb/s not sure how that will scale as more users connect so i'll have to check that as people are on.