[KLUG Members] how do find who is holding my dns records

[members@kalamazoolinux.org]

I am planning on taking the plunge and setting up my own 
DNS servers but I am running into an issue.  A few years 
ago we set a ip/van (Private network) with one of our 
customers using Ameritech and at that time we had them 
register us a domain (lacksdesign.com).  So right now if 
you do a look up on that domain it shows Ameritech as 
the record holder (sorry I do not know the technical 
name).  I need to find out who is above them (again I do 
not know the technical name).  So I can have them point 
to my dns servers.   Is there any why to find that out 
with nslookup,dig and/host?

I need to go above Ameritech as they where no help.

Thank you