Some students are not computer literate. You must be prepared to attend to the needs of these slower students and to allot sufficient time for them to finish their tasks in the computer room. A tip is to put the more able students with the weaker ones. Then you must be prepared to liaise on a regular basis with your opposite number. This is a very important factor that will largely determine the how successful the e-mail project is.
Considerable time is needed initially to co-ordinate student correspondence.
Once the correspondence is up and running, co-ordination becomes easier. You need to establish this with your opposite number from the outset. You do not want an e-mail project to drag on indefinitely. You should limit correspondence to a number of weeks only. You should decide this before you embark on a project, for the same reason as above.