If you can get ahold of it, Talkworks Pro by Symantec is the one to use. I am still using it, although it is out of production and sometimes is a bit finicky in Win2K. I think it came with some of the older versions of Winfax (but not sure), so if you have an older CD, you might check for that.
As a side note, I'm disappointed that Symantec discontinued this product as it was wonderful for my home office! Does anyone else use a product for voicemail on their computers?