Subject co-ordinator. AKA...
Cross-curricular co-ordinator, subject leader. This is not the secondary head of department role, but the wider, and arguably more difficult job of leading and advising a team where none of the group has had specific training in the subject they have to teach. In primary this could be ICT, or physical education, though literacy and numeracy co-ordinators do essentially the same job. In secondary, subject co-ordinators lead those shadowy areas of the curriculum such as PSHE (personal social and health education), which, confusingly, usually includes careers.
Expect a lot of...
I cascade training. This is that wonderful concept modelled on the wedding reception trick, where a flunkey pours fizzy wine into a tall pyramid of glasses. Usually this involves spilling quite a lot of the bubbly; it would be easier to fill the glasses on a one-to-one basis. Cascade trainers know the feeling. In the cascade method the school co-ordinator has a day off to be trained, often alongside their colleagues from other schools in the area. It's comfy, there's a buffet lunch and the trainer has all day to get the message across. Then it's back to school to pass on these golden nuggets to the team; except that the cascade session has to happen at the end of the teaching day on a wet Friday afternoon.
Are you enthusiastic about...
I whatever it is your are leading? Numeracy, literacy, science, PE, sex and drugs (sorry - that's PSHE again). This might seem a daft question. What kind of head would ask a teacher to lead on a topic or subject where said teacher appeared to have no apparent interest? A useless one, obviously.
This is less common in primaries, and in small schools there may not be any choice as to who leads what, but in a number of schools the co-ordinator role appears to be done on a "buggins' turn" basis, or worse, as a sinecure for staff too incompetent to be let loose on a real subject.
Are you good at...
I writing resources? Because you may need to be: the resource situation is often dire, that is with the exceptions of literacy and numeracy, where squillions have been spent on lesson materials. Even where good resources do exist teachers may need to adapt what's on offer for the needs of their particular school. One of the huge advantages of the IT networks and whiteboards now in place in many schools is that teachers can now share lesson plans and materials. Often planning is done collaboratively, but someone still needs to pull the whole thing together and ensure that all the bases have been covered. If you are the co-ordinator, that someone is you.
Does it pay?
In secondary, yes - though sometimes the words "blood" and "stone" come to mind. I recall the job advertisement where the PSHE co-ordinator was also careers teacher and work experience co-ordinator, with additional responsibility for governors and community liaison. And all for a couple of management points.
Primary teachers are often given a co-ordinator's role as soon as they are out of their induction year. There's no specific pay attached because almost everyone has an additional role of some kind.
Is it a good career move?
In primary it's probably essential. The entire basis of primary teaching is dependent on the classroom teacher mastering every subject in the curriculum; this is impossible without a lot of help from colleagues. Many primaries are moving to a quasi-secondary model, with specialist teaching in certain areas. That makes sense as well, as long as the new specialists have had sufficient grounding in whatever it is they are expected to teach.
In secondary schools, responsibility for a subject outside the big 10 is probably not a good career move. PSHE in particular is often a career graveyard, sustained by enthusiasts who know that what they teach is important. Appointing panels are looking for management experience in a mainstream department. Managing a loose and disparate team while writing your own resources may actually be a tougher management job, but don't expect other people to see it that way.