public final class HttpTask
        extends
        AsyncTask<String/* Param */,Boolean /* Progress */,String /* Result */> {

    private HttpClient mHc = new DefaultHttpClient();

    @Override
    protected String doInBackground(String... params) {
        publishProgress(true);
        // Do the usual httpclient thing to get the result
        return result;
    }

    @Override
    protected void onProgressUpdate(Boolean... progress) {
        // line below coupled with 
        //    getWindow().requestFeature(Window.FEATURE_INDETERMINATE_PROGRESS) 
        //    before setContentView 
        // will show the wait animation on the top-right corner
        MyActivity.this.setProgressBarIndeterminateVisibility(progress[0]);
    }

    @Override
    protected void onPostExecute(String result) {
        publishProgress(false);
        // Do something with result in your activity
    }

}

然后在你的活动的某个地方：

new HttpTask().execute(someParams...);