If you want to do this in code, here is a sample:
pd = new ProgressDialog(MainActivity.this);
pd.setProgressStyle(ProgressDialog.STYLE_SPINNER);
pd.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
pd.getWindow().setGravity(Gravity.CENTER_HORIZONTAL|Gravity.CENTER_VERTICAL);
TextView tv = new TextView(this);
tv.setTextColor(Color.WHITE);
tv.setTextSize(20);
tv.setText("Waiting...");
pd.setCustomTitle(tv);
pd.setIndeterminate(true);
pd.show();
Using TextView gives you an option to change color, size, and font of your text. Otherwise you can just call setMessage(), as usual.