It depends on a number of factors.
First, your internet connection speed. Second, your ISP, and your routing tables, third, some connections are 'shared' so the more people in your neighbourhood downloading anything at the same time can slow you down, fourth, the size of the file being downloaded, and fifth the amount of traffic on NWR at the time of download.
If you have a fast connection (cable, say 1.5Mb), with a perfect ISP, and a near perfect routing table, a 3Mb file should come down in less than a minute. This is a very rare occurance however, to have a perfect connection.
If you are on dial-up, say 28.8k, you could expect to wait an hour for the same download.
However, any server along the chain is too busy, your ISP is having problems, or NWR is particularly busy at that time, then a download will take longer. Alot of people have huge routing tables as a result of a low-level ISP and inefficient operating systems that don't allocate routing tables properly...
