getPreviewSize getPreviewFormat

check Camera class getPreviewFormat() API.
get now setting and supported list.

Camera.Parameters param = camera.getParameters();
//get preview format
Log.d("camera", "PreviewFormat=" + param.getPreviewFormat());
//get preview supported format
List< Integer > previewformatlist = param.getSupportedPreviewFormats ();
for (int i=0;i < previewformatlist.size();i++) {
 Log.d("camera", i + " format = " + previewformatlist.get(i));
}

NexusOne is supported NV21 only.
check Camera class getPreviewSize() API.
get now setting and supported list.

//get
Camera.Parameters param = camera.getParameters();
//get preview size
Log.d("camera", "PreviewSize width=" + param.getPreviewSize().width + " heigth=" + param.getPreviewSize().height);
//get preview supported size
List< Camera.Size > previewsizelist = param.getSupportedPreviewSizes ();
for (int i=0;i < previewsizelist.size();i++) {
 Log.d("camera", i + " size width = " + previewsizelist.get(i).width + " height = " + previewsizelist.get(i).height);
}

They are supported list at NexusOne.

 0 size width = 1280 height = 720
 1 size width = 800 height = 480
 2 size width = 720 height = 480
 3 size width = 640 height = 480
 4 size width = 576 height = 432
 5 size width = 480 height = 320
 6 size width = 384 height = 288
 7 size width = 352 height = 288
 8 size width = 320 height = 240
 9 size width = 240 height = 160
 10 size width = 176 height = 144

Source code is here.