Modem spy is ok
There are some software like that, but I like mothem spy becouse it's very small, it detect inmediately modems properties and it works great. You can configure many things, the sound qualitie recording (from mono to CD), a total hiden phone spy recording all incoming and outgoing phone calls. I use it, the record is very clear and people dont detect is being recorder (no sounds at all like someone pick up the phone). And an alternative use is that you can change input recording device to the soundcard and use it like a recorder.