Arriving at a minimum set of technology competency standards for the teachers at your school depends on many things. Look first at what skills your environment demands of teachers. This depends on where the use of technology fits into your instructional and administrative programs. Where the maintenance of student records and intra-school communication depends on the use of technology, standards have meaning and application. So the first rule of thumb in establishing technology competency standards for your faculty is to look first at those tasks that the computing environment you have created enables and requires of teachers on a regular basis.
People learn to do what they have to do.
So basic competencies pave the path to higher competencies. Look at your own teacher training curriculum. As you have built the technology infrastructure at your school you have undoubtedly made an attempt to train your faculty and staff in how to use it. Teachers need to know what they are expected to know. Pulling out the underlying objectives of your faculty training program may provide you with an explicit list of standards.