should be in the disease/treatment section, but anyways...
are the white worms flat or round, and do they float/swim or stick to the glass?
usually these white worms are harmless and feed on bacteria that accumulates in the filter. these are a great source of food for smaller fish.
more or less a general pain in the neck, nothing to worry about though. up the WC's and you should clean them out.
ask Guppy for more info, He would know