I've a lot of time for the Baptist Union mission department. Not only do they have some excellent and concise resources online, but their bimonthly mission newsletter is great, a swathe of events, training, ideas, resources for Fathers Day, world cup, children, small churches, etc. etc. all in one document.
I must confess that I find this much more helpful than the piecemeal CofE system of having a mission department in 43 separate dioceses, plus one in Church House, with a real mixture of quality across the board. I noted last year that there were plenty of resources produced by one Diocese that could easily be linked to from another, to save duplicated effort. If I get round to revisiting that survey of Dicoesan websites this summer, we'll see if any of the ecclesiastical iron curtains that surround Dioceses have been broken through. What are the chances?