I suggest checking out these other questions on Server Fault as well:
File shares for Mac users
What are .DS_Store files and why does OSX leave them on Windows shares?
As far as I know you can not disable the saving of resource forks as separate files (I'd love to be wrong here) as it's part of the design to avoid losing data on a non-HFS or UFS drive in Mac OS X. However it is possible to "veto" these files from being created on the server - but beware of certain programs that actually do require the resource fork (eg. Quicken).
To veto the files taken from the first question listed above:
Additionally you should be aware that over SMB you will notice
._FILENAME files created - this is how OS X maintains the resource fork data and such on other file systems. This can cause an issue for someone on a Windows based machine if they try to open up the wrong file.
It's possible to have the server not allow these files (in smb.conf you can set
veto_files=._*) but where it is in Windows Server 2003 I'm unsure but I believe using this article from TechRepublic should prove a worthwhile starting point.