You may experience that the charger enclosed in the box with your Xperia™ Touch makes noise while charging. This is a known issue, and it is caused by the charging load combined with the Xperia™ Touch being turned on or off while charging. The issue is being addressed at an early stage in the production.
All chargers make some noise, and people may experience the noise differently. If you think that the charger for your Xperia™ Touch makes noise at an abnormal or unacceptable level, contact your retailer. Both the Xperia™ Touch and the charger may need to be examined.