No official reports on whether Ray Allen has made a decision yet, but Miami Heat owner Micky Arison appears to have let the cat out of the bag with this tweet:
Allen, of course, wore number 20 for the Celtics (although he was number 34 for the rest of his NBA career). We know that it wasn't all about the money for Allen, since the Heat could only offer him the mini mid-level exception of about $3 million, while the Boston Celtics supposedly were willing to go to $12 million over two years.
Allen was said to be upset at being usurped by Avery Bradley in the Celtics starting lineup and concerned about a diminished role, and he evidently views joining the Heat as a better chance to collect another ring.
UPDATE: Marc Spears of Yahoo! Sports is the first to confirm that Allen has committed to signing with the Heat. https://twitter.com/SpearsNBAYahoo/status/221419361238384640