FTP or Messenger, etc.

hey guys, I have a mobile user who needs to send me large files over the internet through a cellular connection to the internet via a merlin card with service provided by Sprint PCS Vision. Currently we are using MSN messenger 5.0 which works perfect most of the time but we have been having problems lately with the messenger software itself. On my end it keeps signing me off messenger right when the file transfer is about to complete. Other times it goes without a hitch. These files are too large for emails so that does not work. Can you guys recommend a better alternative? FTP, etc.? If so, how do I set-up an FTP site? I am desperate. Please help.