28kbps modem = 3.5K/second
56kbps modem = 7K/second
64kbps ISDN = 8K/second
128kbps ISDN = 16K/second
256kbps DSL = 32K/second
512kbps DSL = 64K/second
1mbps DSL = 128K/second
2mbps DSL = 256K/second
10mbps ethernet = 1.25 MB/second
100mbps ethernet = 12.5MB/second

The figures on the left are the ones normally displayed on packaging. In practice, you'll get just less than the figure on the right *under ideal conditions*.

Sleepey - the 68K you have is the type of processor your Mac computer has, it's nothing to do with your Internet connection. It sounds to me like you've got a cable modem which allows you to download at 1mbps and upload at 128kbps. This is quite a popular and cheap way to get near-broadband speeds in some areas - it's unlikely you'll be able to get a much faster connection without spending quite a bit more money.

Even if you did this though, you wouldn't see much on an improvement on any but the most popular files on P2P networks - most files would still be shared from machines with much slower connections. If you really need to transfer data very quickly, copy it onto a CD and ***** it.