I came across this steaming method on another bread forum about a year ago. I've modified it slightly, but it's been my preferred method ever since. I find it superior to the boiling water or icecubes in a heated tray approach, but it's probably not as good as baking under a cloche for the initial steaming period (haven't tried that...oven too small).
Anyway, here's what I do.
Put a tray in the bottom of the oven during the pre-heating stage prior to baking.
Soak a piece of towelling material in water (mine's an old handtowel about 100cm x 60cm, but bigger would probably be better, depending on the size of your tray), wring it out, fold it in 4, and microwave it in a covered container for 4 minutes. Meanwhile, boil some water. When the 4 mins is up, whip out the heated tray (the poster who alerted me to this method leaves it in the oven, but I don't like bending over face-first in the vicinity of a steaming tray), evenly lay the folded towelling over the base, pour a little boiling water on the towelling and get the tray back in the bottom of the oven ASAP. Note: you never have it so wet that it's sloshing around. The towel should absorb all the water.
Give it a few minutes, then you're ready to load your bread. I boost the initial steam with a few quick sprays of water around the sides of the oven via a plastic spray bottle as soon as the dough is in, then again a couple of minutes later, taking care each time to get it over with and close the oven door ASAP.
Steaming period is maximum 15 mins (I've taken it down to 12 in recent times, and generally prefer this), so the towelling doesn't scorch. If it does, you need to make sure you moisten it more evenly next time.
Still doesn't provide enough steam to get a really good shiny golden finish on baguettes, say, but for SD breads it's the best domestic oven method I've come across so far (heated nuts and bolts or lava rocks are not for me, but from all accounts that yields a lot of steam if that's what you need).
Hope this may be of help to folks who are not thrilled with their current steaming method.