Those 56K "accelerator" products work by compressing the text content in web pages and cranking up the compression on JPG's, so less data is moved. You're still on a 56K connection, and you won't get any kind of benefit for VOIP usage.
Is some sort of broadband service available in your area? Dialup is just too damn slow to do anything useful, and frankly I don't know why people still buy it. And this is coming from someone who works for a dialup ISP.
