Redirect media audio output to mono bluetooth headset.
Due to Android hardware implementation differences and the assortment of BT hardware available, make sure that you try this before buying by downloading the Bluetooth Switcher Trial. This is a free download from the market that allows you to test hardware configurations.
Froyo only -- 2.2.1 will fix google reboot bug
1) Connect BT headset
2) Run media program (Music, GPS, podcast etc.)
3) Set full volume on media
4) Run Bluetooth Switcher
Audio should play thru mono headset.