if your having a dialup problem you can go to preferences ---> general preferences --> select no internet connection under internet connection settings.(mind you I havn't checked if this functions works in years)
but otherwise if you have an always on connection like most of us;
use a firewall and disable winamp from connecting to the internet is more or less the only way these days.
winamp uses lots of internet resources to function 100%. you can minimize it with your usage like disabling gracenote, not using the autotagger, not using the mini browser. hiding the file info bar in the media library. not streaming anything.
you can more or less get winamp to run without connecting to the internet if you use it the right way.
If your interested in updating/contributing to winamp's tech support greatest hits forumPlease start a thread in winamp's discussion forum with what you would like to see along with your update for review