Directory list slow to load over network

I have a small network at home running Win2k, XP, and Win98 SE on the various machines. After I upgraded some of the machines to Win2k and XP, I noticed a huge difference in how long it takes to browse files over the network. This slowness only exists on the Win2k/XP boxes, the Win98 box is still quick, even when browsing a drive on a Win2k/XP box. After selecting a folder, it takes A LOT longer to list the files and subdirectories when compared to Win98. I’ve seen the same behavior on the network of a company I write software for. What gives? Is there something I can do to make it quicker? I’m curious as to what kinda extra tasks are going on that would cause the added delay. Thanks in advance for any input.