Facebook announced a new version of Facebook Messages today that could put the social networking site at the center of your online communication.

The company describes this as an attempt to consolidate different kinds of online messaging, starting with email, SMS text messages, Facebook messages, and instant messages. Director of Engineering Andrew Bosworth noted that currently, when you want to reach someone, you usually choose different communication methods for each person — you may have one friend who prefers receiving text messages, while your grandmother might only respond to emails.

With Facebook Messages, you shouldn’t have to think about that stuff anymore. You just send a message to the person you want to reach, then they receive that message through the medium of their choice. You can manage those messages on the Facebook site itself, or have them forwarded to email, sent to your instant messaging account, or sent via text message as needed.

“It should feel like a conversation,” Bosworth said. So if you need to step away from your desk during an IM conversation, you don’t have to tell them, “Be right back.” Instead, you step away and just continue the conversation via text message.

Facebook isn’t just consolidating communication media. Facebook Messages also ditches the idea of email threads grouped by subject. Instead, all of your conversations with someone show up in a single thread, which could theoretically contain the entire history of your communication with someone.

Facebook is also using your contact list to prioritize your emails. Messages are grouped into three areas — “messages”, “other”, and “junk”. Messages come from your Facebook friends, “other” comes from folks who aren’t friends, and junk contains the messages that are flagged by the spam filter. Users will be able to shift contacts into different groups. So if you’ve agreed to be friends with thousands of people, you don’t have to prioritize messages from all of them.

The company will be gradually rolling this out over several months. (I’m part of the first wave of outside users, so I’ll probably write a post this afternoon outlining my impressions.) As part of the rollout, users will be able to activate Facebook.com email addresses. Despite that feature, and despite speculation about the service as a “Gmail killer”, Facebook chief executive Mark Zuckerberg said, “This is not an email killer.”

You can read more details in Facebook’s blog post.