Nintendo has confirmed to MCV that they are going to drop the price of the DSi in the UK. There was no hint of by how much but they did say it would be from the 18th of June.
If the price reduction in Japan is anything to go by MCV suggests the price drop could be between £20 and £30. The reduction only applies to the standard DSi and not the other models, the DSi XL and DS Lite.
All this is of course in preparation for the E3 announcement of the 3DS later this month.