This has got nothing to do with Hebrew names but simply writing Hebrew characters in general to their English sounding equivalent.
What I mean is, Many people have a Hebrew name that is completely different and not translatable to their English name (If they are not using their Hebrew name as their English name).
For example - אַבְרָהָם is phonetically Avraham, and an Israeli in a Hebrew speaking place or visiting an English country may be called that, but an English person with that as their Hebrew name would most likely be called Abraham.
I am not aware of any service that can do this automatically - other than Google Translate as Hello71 said, simply type in the Hebrew and it will read out to you the English.
Edit -
A good site you may like is http://www.learn-hebrew-names.com/, It will show you the Hebrew, the phonetic English version and the English translation (if available). It also as a bonus can tell you the meaning of the name!