INTRODUCTION (Question follows)
I record using streamer (part of xawtv). Normally, I record Audio only, but sometime Audio and Video. The reason I use streamer is that it is controlled by Command Line parameters, so I can run it from a script – and it can record Audio and Video or just Audio. Once recording is complete, I split the Audio up into tracks to burn to an Audio CD. In order to know approximately where to split the recording, the script also starts another program which writes the elapsed time since it started running to a file each time I press a button (or the space bar). Since the two programs are started by the script, the times logged in the file are well synchronized with the recording.
The problem with using streamer is that it does not have a VU meter of any kind – so I don't know until the recording is complete if it is too loud or too quiet (or just right).
If I am recording just Audio, I could use Audacity which would be wonderful – but I would not be able to synchronize my timing program so well with the start of the recording, and I could not record Audio/Video.

QUESTION
Is there a way that I can send the same Audio feed into streamer and some other program which will give me a visual indication of the recording levels? I have seen reference to 'jack' – but that seems to want everything which works with it to be compiled to interface to it. If jack will do what I want, is there a guide to how I would use it?

If you use the spacebar, then why not use Audacity (a gui app, for audio only). But yes, Jack, the advanced sound framework for Linux and OSX does that really, really well. PulseAudio, the standard audio framework in Fedora 10+ is also capable of doing this, but it will requier more work to set it up as only few users use Pulse for that kind of thing. But it does handle multiple audio sources/destinations.

Having looked at Audacity, I am aware that I can select the input source I want to use. Similarly, with streamer, I can select the input source I want to use. So, if Jack can open the source that I would normally use for streamer and give me 2 'ports' then I could have my 2 applications use those 2 different ports and we would be happy.

Reading the documentation for Jack, it does not provide me with 2 ports, it gives me "an API that does several things". So I look at the simple_client.c which "demonstrates a complete (simple!) JACK application" - but it has 1 input port, 1 output port and a client. I am not sure what the client would do.

The write-up of Jack starts by suggesting that it can do what I want, but then seems to suggest that I am going to have to re-write Audacity to use an API - and I don't want to re-write things that work.