Any DVD movie which is backed up using Slysoft's "AnyDVD" will result in a "Region Free" backup. I don't know anything about other decryption softwares because I only use AnyDVD.
But it does not change the Video Format of the original DVD (ie NTSC vs PAL). Dont confuse Region Encoding with Video Standards. North American DVD releases are made to the NTSC standard. UK DVD's are made to the PAL standard. If your UK player is designed to play only PAL (most likely), and your TV will only display PAL (most likely) then you will not be able watch foreign NTSC format movies that you buy on (for instance) Amazon.com nor the backups that you make from them. In other words, AnyDVD removes region encoding but does not convert between video standards.
If buying USA "NTSC-standard" movies for your collection is going to be a regular habit, then what you really need is a DVD player that "hardware-converts" your NTSC Standard DVDs (and backups of same) to output to your PAL based home entertainment equiptment.
Some members may suggest softwares that can convert your backup from one standard to another but using a software-based method of conversion is complex, processor intensive, time consuming, and produces less than acceptable results. For one thing the lines-per-inch resolution and the frame rates of the two standards are different so you will get "jittery" playback on fast action scenes. And, since there are billions of bytes of data to crunch, even a powerful computer takes a long time to convert from one standard to another. One little glitch during that process can result in an unplayable backup. And you will have to do conversion backups over and over for each NTSC DVD released movie in your collection for them to play on your UK PAL based equiptment! This explaination is just skimming the issues of software-based conversion but you can see what I mean by "less than acceptable". I suppose software conversion could have improved since I explored the issue 1 1/2 years ago but I solved my conversion problems on a hardware/firmware level by buying a "Multi-Format" DVD player that outputs foreign made DVDs to my NTSC based WS TV (I'm in the USA).
You want a player that plays both formats, to either an NTSC or PAL TV, for a much more desirable solution.
In this posting I provide a link to MindLogic, a California, USA based supplier of such players and I believe they ship out of country (to your UK).
There are also several links on the MindLogic website that explain how the player converts between the two standards.
This is a link to the entire 3-page thread that the above posting is from so give the thread a read through to understand the issues because a slysoft software engineer contributed answers and expainations that will educate you.