I have a 2000 reg 1.2 8v punto, and its developed a strange noise.

When im accelerating from 1st gear to 2nd gear, and then to 3rd gear...the cars seems to make a "whizzing" noise? It sounds like its coming from under the bonnet, but i cant think what it is? It only seems to do it when im accelerating through the gears?

Any idea's guys?