Migrating to IPv6 sounds like Charles Dickens: "It was the best of times, it was the worst of times" (A Tale of Two Cities). NOTHING about IT is as simple as it sounds....
IPv6, aside from the hoopla over IPv4 running out of addresses (beleive it or not), has real benefits. Mobility, security, quality of service, intelligence. . . . If you want to know how the move is going, pay attention to the US DoD, which is probably the largest organization in the US to commit to IPv6. Elsewhere in US, mostly ignored. But it seems to be real popular everywhere but the US.
And that is the biggest point - why IPv6. Do you have partners going to IPv6 that necessitates you migrating? What about your applications? If you develop applications, then you could get significant benefit. What about your hosts? internal and external networks? These are the challenges, which are not necessarily insurmountable. And there is a lot of payoff as I said above.
Searchnetworking has a good bit of information on IPv6. Also, go to the ususal suspects:
Cisco (as well as many other network vendors)
[If you aren't familiar with US DoD, search for Stenbit (former DoD CIO who started IPv6 migration) or www.defenselink.mil)]
There is a lot of information and guidances here. The big thing to watch for is interoperability and functionality of your applications, workstations, servers, and networks.