Some may have problems due to their transmit buffer being set too low as recommended by some users. Here are instructions to raise the transmit buffer for your network adapter in order to allow java to send the full blocks of data.
For Windows XP:
right click on my computer icon
click manage
then device manager
then network adapters in the right panel and click the one that you use
click the advanced tab for your network adapter
there should be a item called "transmit buffers" here
click "transmit buffers" and change the number to 512 and press ok
For Vista/7:
go to control panel
click network and sharing center
press change adapter settings
right click your network adapter/wireless card and click properties
then click on configure under the adapter name
click the advanced tab for your network adapter
there should be a item called "transmit buffers" here
click "transmit buffers" and change the number to 512 and press ok
Woo Hoo!. Are you running any mods like hey0 or llama?
I am running MCAdmin, does the server work for you?
