What should I charge ?????

[saintpeta]

Thinking about doing some part-time consultancy work for a school (securing accreditation for the school) but its been so long since I've been in the loop I don't know what the going hourly rate should be! Can any one help as to what I should charge per hour or has anyone done a similar job or point me in the direction of a website I could compare? I don't want to charge too low but obviously would like to know the going rate for a managerial job like this.
Thanks