How long does it take for the changes to DNS information submitted through Manage Domains to take effect?

Domain Name Servers must be registered with a central Registry, NSI Registry. Twice a day, at 11AM and 11PM the root and COM, ORG, NET zones are updated by NSI. This update includes all domain registrations and modifications up until then. The zones are then progressively placed onto the root servers (the servers that allow your domain to be available on the Internet). This takes between 24 hours and a few days.