There are mod chips around that add multi region support. Ive just fitted a WiiKey to mine. Although just checking the feature list, it adds NTSC to PAL machines, it doesnt seem do the reverse (PAL on an NTSC machine). Alternative mod chips may do it though.
That said, you could just order the games from the likes of dvdboxoffice.com, and they will still be cheaper than the UK prices.
Nintendo will sell you a UK spec power supply for about £20. I did that with my US Gamecube.