large file replication

I'm currently replicating multi-gig files across our WAN via scp and am 
in need of another tool.

When the WAN flaps, the file transfer fails and has to start over from 
the beginning of the file..  This wouldn't be so bad if I just had one 
large file, but I have 50.  If one fails, then I'm just that much 
further from completing my goal. 

Does anyone know of a tool that would allow me to transmit the files 
across the WAN, and pick back off where I left off after a WAN flap?  If 
I've transmitted 9 gigs of a 10 gig file, I do not want to have to 
resend the original 9.    
Thank you,

Michael