Facebook is holding some sort of Android related event next Thursday in Menlo Park and has sent out a slew of press invites. Nobody is sure exactly what they have in store, but speculation runs from a better (working) Android application to the rumored HTC Myst Facebook phone.
There's also rumor of a "deeply integrated" Facebook experience built into the devices people will want to buy. Zuckerberg has been pretty adamant that building a phone is the wrong way to go, so this is certainly a possibility. We're not sure exactly what to expect, but we know Facebook does things in grand style. We'll know more next week.