Unfortunately, there's not a lot you can do as far as I know. Unless you are getting extremely slow speeds from your 56K (ie connecting at only 33.6 or so) you really can't do much. I generally connect at 49333 or 45666, both of which are quite good for dial-up, but they pretty much depend upon the condition of your phone line. If you are unlucky enough to have a noisy line, then you're pretty much stuck with connect speeds around 33600.
Zenmervolt