People have been searching for the English version of Utau, but I have translated it, so that now I can help you can download it.
S1- Click here for the link to the site.
S2- Click the Download named:
■2013/9/5 最新版 v0.4.18e
S3- Save and name is "Utau" or something along those lines.
S4- Depending on what you use, you need to open that file and it will open the Installation Wizard.
S5- If you are not fluent in Japanese, like me, the first thing that pops up will boggle you, so just follow as I say. Window one says nothing, but welcomes you to the installation process.
S6- It will ask you where to save it, and whose account it's on. If you want it on yours only, click the bottom bubble, but if you want it on the program to be on all, click the top bubble. When you are done picking where it goes and who uses it, click the Next (N) button.
S7- It will ask you to click the Next (N) button. This confirms that you want to download this. It took a second to have it start, but don't click anything while it's working.
S8- Done. You have finished. That wasn't so hard! Now to just toy around!
I hope this helped in some way, if not tell me what went wrong and I will try to help.