All versions of the Nexus S from Google, whether through AT&T, T-Mobile or Sprint, are free with a two year contract at Best Buy, Best Buy Mobile stores, and on, tomorrow.

The sale begins at 11pm tonight (local store closing times vary) and goes until midnight, tomorrow night, (August 3).

Current prices (before the sale) as listed on their site are – the Nexus S 4G from Sprint, free, the Nexus S from T-Mobile, $99, and the Nexus S from AT&T, $99. Prices quoted with purchase of a two year contract with the indicated carrier.

Reviews for the Nexus S, which runs on the Android 2.3, Gingerbread, platform, range from 4 to 4.4 out of 5, depending on the carrier, on Best Buy’s website. The phone is designed with a 4 inch display, has wifi, Bluetooth, gps, front and rear facing cameras, near field communications (NFC), and 16Gb of internal memory.

The free Nexus S deal is not limited to new customers – it applies to upgrade purchases with two year activations as well.