You first heard about it on MadonnaTribe last month, and now you can get it from iTunesMusic Store.
Madonna's "Celebration - Feat. Akon" is available to purchase as a digital single in a stand-alone format and the related iTunes page features a customized cover highlighting the contribution from the guest artist.
Although listed with a release date of November 9th, the track happens to be available to purchase from this morning on most Music Stores worldwide.
Thanks to Rhythmotronic, Kent and Réjean.