Here is a quick example of how to programmatically access ActiveMQ MBeans to monitor and manipulate message queues...

First, get a connection to a JMX server (assumes localhost, port 1099, no auth)
Note, always cache the connection for subsequent requests (can cause memory utilization issues otherwise)

JMXServiceURL url = new JMXServiceURL("service:jmx:rmi:///jndi/rmi://localhost:1099/jmxrmi");
JMXConnector jmxc = JMXConnectorFactory.connect(url);
MBeanServerConnection conn = jmxc.getMBeanServerConnection();

Then, you can execute various operations such as addQueue, removeQueue, etc...

String operationName="addQueue";
String parameter="MyNewQueue";
ObjectName activeMQ = new ObjectName("org.apache.activemq:BrokerName=localhost,Type=Broker");
if(parameter != null) {
    Object[] params = {parameter};
    String[] sig = {"java.lang.String"};
    conn.invoke(activeMQ, operationName, params, sig);
} else {
    conn.invoke(activeMQ, operationName,null,null);
} 

Also, you can get an ActiveMQ QueueViewMBean instance for a specified queue name...

ObjectName activeMQ = new ObjectName("org.apache.activemq:BrokerName=localhost,Type=Broker");
BrokerViewMBean mbean = (BrokerViewMBean) MBeanServerInvocationHandler.newProxyInstance(conn, activeMQ,BrokerViewMBean.class, true);

for (ObjectName name : mbean.getQueues()) {
    QueueViewMBean queueMbean = (QueueViewMBean)
           MBeanServerInvocationHandler.newProxyInstance(mbsc, name, QueueViewMBean.class, true);

    if (queueMbean.getName().equals(queueName)) {
        queueViewBeanCache.put(cacheKey, queueMbean);
        return queueMbean;
    }
} 

Then, execute one of several APIs against the QueueViewMBean instance...

Queue monitoring - getEnqueueCount(), getDequeueCount(), getConsumerCount(), etc...

Queue manipulation - purge(), getMessage(String messageId), removeMessage(String messageId), moveMessageTo(String messageId, String destinationName), copyMessageTo(String messageId, String destinationName), etc...

Summary
The APIs can easily be used to build a web or command line based tool to support remote ActiveMQ management features. That being said, all of these features are available via the JMX console itself and ActiveMQ does provide a web console to support some management/monitoring tasks.

See these pages for more information...

http://activemq.apache.org/jmx-support.html
http://activemq.apache.org/web-console.html