Tom,
I'd start with the link protocol and choose PPP between them both. You'll then need to make some decisions regarding the routing protocol, OSPF or BGP; would be obvious selections.
in the serial interface
int serX
encapsulation ppp
ip address X.X.X.X 255.255.255.252
no shutdown
router ospf 1
network X.X.X.X 0.0.0.3 area 0
I don't think that the Juniper config will be much different.
I hope that gets you started.
Tony