I have a need for a hearing aid application.

Quite simply, I want to stick my earphones in my ears[1] and plug them into my N900, place it in the middle of the table in front of me and for an app to amplify the sound picked up from the N900's microphone and play it through the headphones.

Even better is if I can use my bluetooth headphones, so I can be further away from the device than is convenient with wired headphones.

Mono only, please - I don't know if the mic on the N900 is stereo or not, but if it is, the sounds should be mixed to mono for obvious reasons (I suppose this could be optional).

Regards,

Max.

[1] in my case, just one since only one of my ears works