Possibly to copy files from one farm to another in SharePoint?

I would be doing this from a custom workflow activity.

Does anyone k开发者_运维百科now if this has been done before? Any suggestions on where to start?

I am an admin on both farms.

I'd suggest you look into using the Copy web service provided by SharePoint

/_vti_bin/copy.asmx

Use web client and copy.asmx check this link might help http://social.msdn.microsoft.com/Forums/en-US/sharepointdevelopment/thread/4556873e-e2e0-4b26-99f2-70f0b0e50c2c