small digital camera for above and below

I am looking to buy a small digital camera that I can also put in a housing and hopefully get some decent underwater pics.

The ones that have been recommended to me (by non-divers) are:

Pentax Optio S4 or S4i or the Canon S500.

I don't mind if I have to get an external strobe flash but dont know which compact digital cameras have housings and facilities for an external strobe.

I will also use the camera for close up pics (jewellery) topside.

I would really appreciate some advice.

Thank-you,

Mikey

I owned a Canon s-50 and was quite pleased with the quality and ease of use. Has good array of manual settings for a small point and shoot type camera.The only available housing is an inexpensive Canon that is rated to only 90 ft...althought Ive had mine deeper with no problem.