Identica is a commercial offering based on the StatusNet package.

StatusNet is an open source microblogging server implementation formerly known as Laconica. It implements the OStatus stack on top of HTTP.

It's most important feature is the ability to allow for decentralized microblogging - that means, having a federated interserver protocol to inform remote subscribers of microblog messages.

It suffers from scalability and privacy limitations.

Cross-publishing microblogs from psyced to StatusNet

Since StatusNet offers a Twitter-compatible API (See [1]) you can use psyced's OAuth capabilities also to publish your PSYC microblogs to Identica and other servers running StatusNet software.