As of 2009, linezolid is the only oxazolidinone antibiotic available. Other members of this class have entered development, such as posizolid (AZD2563), ranbezolid (RBx 7644), torezolid (TR-701), and radezolid (RX-1741).
The only major competitor is Pfizer's Zyvox...which does around 1.8 billion in sales.
I posted about this a month ago. Radezolid is not as effective as TED and TED is much further along the approval process