I never like too much the concept of "helper classes",
First of all I tried to found some written reference to "Helpers" http://patternshare.org/default.aspx/Home.AllPatterns with no luck... But it seems to be any a class with static methods.
I also found http://patternshare.org/default.aspx/Home.PP.UtilityComponent wich I think should be deleted.
Both are examples of CodeSmells, more info on this here: