the permit process can take 2-3 months (that is, for the USFWS intrastate commerce permit), however, some states, like Illinois, also require a state E & T permit from the DNR; that is usually a quicker process.
In terms of availability, most of us who breed eastern indigos are sold out for this year, however, if you go to www.indigosnakes.com you can get a listing of the various indigo breeders and perhaps you can get lucky. It is still early enough to get on most people's waiting list for next summer.
Rob Carmichael, Curator
The Wildlife Discovery Center at Elawa Farm
City of Lake Forest Parks & Recreation, IL