On Cham Island you will not find too many accommodations. I passed a nice looking homestay on the main road along the beach in the village of Bai Lang, though I don’t know what the rooms are like. There are one or two further places to stay north of the village – just take the road up the hill from the pier and passing the football pitch.
In the other village, Bai Huong, there are apparently some homestays, but I cannot advise where.
One popular option at the island is staying on Bai Chong beach – in a tent. It is part of some trips organised by the dive outfits in Hoi An. Here is my review of my stay there.