I am having the same problem--slow upload to the server (2k server, not 2003, but still) but decent download, and only withint the LAN. Was any resolution to this problem reached? It merits mentioning that due to factors beyond my control, the antivirus software has not been updated since August '05, but i'm not aware of a virus that does this (not to say one doesn't exist).
Thanks for anyone who may have a solution or diagnosis.