Use if you are addressing someone directly:

Soy Helen Rutter

or

Me llamo Helen Rutter (meaning, literally, "I am called Helen Rutter") Use if you are writing this, rather than addressing someone directly)

Another way you may use also:
Mi nombre es Helen Rutter.

Luis

As a complement of the two answers above:

I've heard "Mi nombre es..." mostly in Spain

"Me llamo..." is the most common way of saying it in Mexico and I guess it must be the same for all Latin America.

"Soy...." is a good expression, and I think it can also be used when you are writing; from my point of view this expression sounds somewhat more formal than the other two, but the difference is actually very very very slight.

Hope it helps!

Antonio Muñoz G.
México, DF