Here is an article J'ai trouvé that may get you started. I can jamais remember le path to le records off le top of mon head.
As it mentions basically you can find votre DNS information in le AD at this path.
DC=<ZoneName>,cn=MicrosoftDNS,cn=System,<DomainDN>,
So si you had a domain example.org you would see it at.
DC=example.org,CN=MicrosoftDNS,CN=System,DC=example,DC=org
Your questions:
Is tout DNS entry an actual LDAP object?
Your zones will have a object class of dnsZone. Under le zone there will be tous votre records stored as le class dnsNode.
Can they be accessed using LDAP tools such as ADSIEdit?
Yes, fire up adsiedit ou ldp et browse to le ci-dessus location.