To bridge from ActiveMQ to another JMS provider (or other kind of transport completely), we recommend ServiceMix
the Apache 2.0 licensed open source JBI compliant ESB.
For example here is an example of how to create a message bridge from one JMS provider to another (such as from MQSeries to ActiveMQ or from WebLogic JMS to ActiveMQ). Of course ServiceMix can handle many other protocols and transports, so its easy to go from HTTP to JMS or JMS to email etc.