the product you are looking for is called a rainsleeve. They are sold by Optecha and I think they can be ordered direct from the company. The last time I looked they were six dollars for a package of two. They are fairly durable and reuasable. I'm not sure but B&H might also carry these. These are for DSLR cameras only and would be way to big for a P&S.
Thanks. They must have dropped the product. I just looked on the Optecha website and could find no such product offered. I'll keep looking.
Rusty