Thanks John.
What happened is I misinterpreted a review I read on Amazon. Some chap said: "The only difference I can see between my optio 555 and the S5i are the advanced operational facilities, such as manual control of shutter speed and aperture". Not knowing anything about the 555, I assumed wrongly that he meant the S5i had the manual control... I realize now it's the other way round...
Never mind, I'm only a little disappointed. My S5i is great (and a lot cuter & cheaper than the 555!)

Received my Optio 5Si this morning. One of my reasons for choosing it was the promised "manual control of shutter speed and aperture". Spent all day "playing" with it and studying the manual but cannot find any way to choose my prefered shutter speed. Help! Thank you. Martine