It is just a matter of getting an inet6 prefix from your RIR/LIR, and configuring it in your network. IPv6 is not hard nor is it difficult to implement, and its nitty gritty details are actually far more logically sound then IPv4. (ARP is a major paint point for instance in large networks, so is IP broadcast traffic).
Most large WAN networks have a core which is either label switched (MPLS) and this doesn't care about anything in regards to the protocol which it is transporting, or is doing dual stack already.