See bottom of post for update.
These wedges from Belle by Sigerson Morrison retail for $240 at Net-A-Porter.
DSW's No. 704b Cat wedge will give you an incredibly similar look for $99.95 (on sale from $198). They're also available in tan and you can click on the photo below to purchase. (Use code FLOWERS for $15 off your purchase of $69+.)
*Update - 5/18/10* - Charlotte Russe now has a version of the Belle by Sigerson Morrison wedges (although the back is different on these) which retail for $35 and also come in black. Click here if you're interested in purchasing.