Saturdays aren’t usually the most popular product release days, but when it comes to RIM, we suppose that anything is possible. Rumors are bubbling that the much anticipate BIS upgrade to version 2.4 will show its face sometime today, September 15th. This upgrade will bring a host of improvements, including vCard, MP3, and PDF/RTF attachment support, among many others. One of the biggest attractions is the ability to log into your BIS account from your ‘Berry without a username or password, with your device acting as de Facto identity validation. T-Mobile already allows this feature, we believe, AT&T and other carriers don’t. We’ll keep our ear to the streets and let you know if it does, in fact, go live.