According to Matt Larson of Verisign, the .com zone is in production as a DNSSEC signed zone as of 1500 UTC today (11am EDT)! This is a big step in helping to eliminate islands of trust given a linked chain up through .com to the root zone.
Now validating resolvers (recursive or caching servers) need be configured with the root zone's public key as trust anchor to validate .com subzones. This along with automated trust anchor rollover per RFC 5011 , puts ongoing management of validating DNSSEC servers on "auto pilot." As the root zone rolls keys, the RFC 5011 process enables validating resolvers to roll with the root!
On the flip side, signing your authoritative zones still requires some ongoing configuration and updating (unless of course you're using a policy-driven signing DNSSEC server such as BT Diamond IP's Sapphire Sx20 appliance!). If you're within the .com domain subtree, you'll need to provide your Delegation Signer (DS) records to your ISP for each of your KSKs, assuming of course your ISP supports DNSSEC! If your service provider hosts your DNS, then they may offer DNSSEC signing as part of their services.
This is a big day in the history of the Internet. Congratulations to the Verisign team for this monumental achievement!