PHILADELPHIA - McDonald??s announced earlier this week the introduction of the McCafé Shake, now available in restaurants and a treat that the restaurant chain hopes "will change the way customers experience" its milkshake.

Available in the three McDonald??s milkshake flavors (chocolate, vanilla, and strawberry), the shake is served in a clear McCafé cup and topped with whipped cream and a cherry.

McDonald??s also is reintroducing the Shamrock Shake, available in stores now through March 31 with a portion of the proceeds from each Shamrock Shake sale benefitting Ronald McDonald House Charities (RMHC).

Through March 17, McDonald??s is holding a "social" fundraiser, during which customers can check-in on foursquare at any restaurant in Philadelphia and send their check-in to Twitter with a @McDPhillymention. For every check-in received, McDonald??s will donate $1 to RMHC. And each customer who participates will receive a coupon for a free McCafé Shake.

"We are excited to introduce customers to the new McCafé Shake experience through our 'Social' fundraiser," said John Durante, president of McDonald's Restaurants of the Philadelphia Region Owner/Operator Association. "We are also encouraging our customers start checking-in on foursquare to support this terrific cause."