shopkick is expanding to the Android platform, effective immediately.

shopkick is a free (and only) app in the Android Market that rewards shoppers for walking into participating retailers, including Best Buy, Macy’s, Inc., Target Corporation, American Eagle Outfitters, Inc., Simon Property Group, Inc. malls, Sports Authority and Wet Seal, Inc., and for interacting with partner brand products HP, Procter & Gamble and Kraft Foods.

The shopkick app verifies the actual presence of a shopper by detecting a “shopkick Signal” coming from the shopkick transmitter located in each participating store. The user can control privacy because the detection happens on the mobile phone.  Once a shopkick Signal is detected, the app delivers reward points called “kickbucks” to the user — just for walking through the door.

Users can then redeem kickbucks at all partner stores for instant gift card rewards or for Facebook Credits to play games online, song downloads, hotel vouchers, specific products, and can even donate to their favorite charity. 

Press materials say that by Black Friday, more than 1,000 individual stores and over 100 of the country’s largest malls will have fully deployed shopkick’s technology.