They have compute nodes with GPUs. From their website:

  22 GB of memory
  33.5 EC2 Compute Units (2 x Intel Xeon X5570, quad-core     “Nehalem” architecture)
  2 x NVIDIA Tesla “Fermi” M2050 GPUs
  1690 GB of instance storage
  64-bit platform
  I/O Performance: Very High (10 Gigabit Ethernet)
  API name: cg1.4xlarge

So they have new awesome Fermi GPUs but the instances cost $0.50 more per hour than the standard HPC compute nodes. Generally exciting for anyone with GPU code and the desire to run on a cluster.