My cyclocross handlebars are really irritating, please help.
I am assuming that you are talking about the handlebar. It is not an easy swap - you would need a new flat/riser bar, new shifters (to match the existing gears), new brake levers (to match the existing brakes), more than likely new cables and housing, plus some grips. Depending on the level of quality of the shifters...it could get very expensive. It could be more cost effective to sell that bike and buy a flat bar commuter.
If it is a comfort issue, there are things that you can do to make the bike fit you better...you don't say why it is irritating.