You can use this class , I have used this in many apps.
package com.your.package;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.StatusLine;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import android.util.Log;
public class RestPost {
    String url;
    List<NameValuePair> nameValuePairs;
    public RestPost(String str, List<NameValuePair> params) {
        this.url = str;
        this.nameValuePairs = params;
    }
    public String postData() {
        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost(this.url);
        StringBuilder builder = new StringBuilder();
        try {
            httppost.setEntity(new UrlEncodedFormEntity(this.nameValuePairs));
            HttpResponse response = httpclient.execute(httppost);
            StatusLine statusLine = response.getStatusLine();
            int statusCode = statusLine.getStatusCode();
            Log.d("RestClient", "Status Code : " + statusCode);
            HttpEntity entity = response.getEntity();
            InputStream content = entity.getContent();
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    content));
            String line;
            while ((line = reader.readLine()) != null) {
                builder.append(line);
            }
        } catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
        } catch (IOException e) {
            // TODO Auto-generated catch block
        }
        return builder.toString();
    }
}
To use this...
List<NameValuePair> pairs = new ArrayList<NameValuePair>();
pairs.add(new BasicNameValuePair("user_id", uid));
pairs.add(new BasicNameValuePair("auth_token", auth));
pairs.add(new BasicNameValuePair("topic_name", TName));
RestPost post = new RestPost(Constants.ForumAddTopic, pairs);
String Response = post.postData();
Hope it helps...