Depends on (a) how tied to a particular vision of the song you are, and (b) how complex it is. If it's three chords and the truth, an arrangement will likely evolve if you play and sing, and they make their own bits up. If it's got some wild and wacky chord changes and abrupt changes of pace, that won't work though, and you've probably got your own vision of it anyway. In which case, a quick demo recording of your arrangement is needed.

We're not talking huge quality here, and Audacity and a PC mic are plenty good enough for the job. Click track of the right sort of length, then record a rhythm track to hold it down whilst playing back the click track. Then any other essential tracks (maybe a lead guitar) whilst playing back the rhythm and click track. Then fill in vocals. This might seem OTT, but it'll give you something your band members can stick on a CD or MP3 player and listen to.

The other advantage of doing that is that although you might think you have the arrangement all planned out, in practise once you're putting it together yourself, you can try out other ways of doing it yourself and get it nailed.

If you give them written chords they'll have them on the floor for the rest of their lives. And never use dots for folk.

Bullshit. If you've never needed written chords or dots, chances are that what you're playing is trivially simple, or that accuracy to the original tune is irrelevant for you. Most bands aim to do better than that.

Of course, if your band *do* have the written chords on the floor forever, it's more likely that you just need better musicians in your band! :-/

Graham.