margin of error - Confidence level

[psrs0810]

I sent out a questionnaire to hundreds of people (614) and recieved 154 responses.
Some of the questions have a yes/no answer (or another binomial response/answer). So for one of them I received 69 yes and 85 no.
What I want to add to my answers/graph is a margin of error (±) for those that misinterpreted the question.
This is where I am getting stumped. In excel, for confidence level, it asks for a standard deviation. I don't know how to calculate a standard deviation on yes/no responses.

Or is there another way to calculate a margin of error?

 

[SydneyGeek]

Start here, and follow the link to standard deviation and standard error calculations.

Denis