Hey Marni? Have you checked out Amy's video on making a center pull ball? If you don't have a ballwinder (or made one yet) I am happy that I can wind them like this, I don't have any trouble with my yarn twisting like it does when you take it from the outside of the skein. taking it from the outside you have to coral the sucker so it doesn't roll around, this way you can put it in a bag or what-have-you and keep it clean but it stays put
Video is here
some knitting books will have a description of the procedure as well...
Also, you may want to locate the Stitch and Book book, there's a page in there on how to cheeply make your own Nostpinde which is a wooden "thingie" also used for winding yarn into balls that pull from the middle. you make it out of a chairleg you can buy from Home Depot as it is turned on a lathe and has the grooves for sort of holding the ball to start with.. You have to see the pic for that to make sense, but search the web for Nostepinde (Nostepinne, it's spelled different ways) to see what one looks like