Tasker now supports BT device detection on Android 2.0+.
While Tasker not yet supports detection of bluetooth devices, BlueDock does. You can get it on the market, for $1.
You will also need Manual Intent Shortcuts - also on the market, for free.
You can use this to automatically start playback of your music or to listen to your podcasts once you have just switched on your bluetooth headset - no need to even take your phone out of the pocket. You can even have different tasks for different headsets, so that your volume will be adjusted to the specific headset you're using just that moment.
You might also want to start the car dock app or some app like Waze, once your phone connects to your bluetooth car stereo or handsfree.
- install BlueDock
- install Manual Intent Shortcuts
- set up a task within Tasker that does whatever you want done each time - for this example let's assume the task is called "Play music"
- start BlueDock
- click on the device you want to configure a task for
- you can select Connect as well as Disconnect (*)
- select "Shortcuts"
- select "Manual Intent Shortcuts"
- fill in the following fields
- Shortcut Name: whatever you like - I don't know whether you can leave it empty
- Action: net.dinglisch.android.tasker.ACTION_TASK
- Extra key: task_name
- Extra value: Play music
- leave the other fields empty
- select Broadcast
- press Ok
(*): Connect will be sufficient if you only want to start playback. Disconnect will come in handy if you want to set your Google Talk status or want to re-enable location based profiles that you had disabled while the headset was on.