DTP Authors should have received notice from Amazon via an announcement email on August, 6, 2010. For those who have books listed in the US DTP Platform, most will transfer over automatically to the UK Kindle Store with converted pricing.
You can check this by going to your DTP Bookshelf and clicking actions on any one of your titles. If it has been transferred, it will give you the option to: See Book in UK Kindle Store. Of course the reviews have not crossposted yet it seems.
If your book is not listing in the UK and you feel it should be or you want it to, you might need to make some changes to your Publication Rights. For each title, you will need to Edit Book Details, then in the Content Rights section, you need select either Worldwide Rights -- all territories or Individual Territories and then select which ones you have the rights for.
Most self-published authors hold all the rights to their work, so in this case, it is best to just select Worldwide and be done with it.
As for pricing, you have two options: you can have Amazon automatically calculate the UK price based on the US list price, or you can enter a price of your own.