Arpasing is a method for doing English in UTAU. By using specially formatted arpabet reclists, you can automatically OTO them with Moresampler, and use a plugin called Arpasing Assistant to edit USTs and automatically convert words to phonemes.
If you want to learn how to make an Arpasing voicebank, and find lots of other useful resources (such as a list of voicebanks and USTs to use), here's the website I've made:
http://arpasing.tubs.moe
All of the resources are also mirrored onto UTAforum Resources.