Best small camera for macro

I just got back from a trip to PNG where I saw a lot of people using small point & shoot cameras in housings, getting absolutely amazing macro shots. I'm thinking about getting one to carry around as a second camera when I've got my rig set up for wide angle.

Does anyone have any recommendations on a good setup for this? Would love to hear pros and cons from actual users.

Thanks in advance for your comments.

Bonnie