From Artkrush #76:

Six artists are vying for the opportunity to erect a sculpture on the empty 1840s plinth in the northwest corner of London's Trafalgar Square. Competing for the commission are Bob & Roberta Smith, with an eco-friendly sign promoting art, not war; Anish Kapoor, with an arrangement of five concave, colored mirrors; Antony Gormley, who seeks volunteers to stand on the structure for an hour at a time; Yinka Shonibare, who proposes an enormous glass-bottled replica of the HMS Victory; Tracey Emin, with a life-size model of a meerkat; and Jeremy Deller, who wants to install an actual destroyed car from Iraq.

I think that's the same plinth where was the larger-than-life statue of multiple-amputee Alison Lapper (depicted pregnant).

The BBC has the further scoop on the new shortlist.