Italian Valves (come on Sheldon, add this to the list) look for all the world like Presta, in fact almost identical externally - difference is that you can remove entirely the valve bit on a Presta that normally you just unscrew a couple of turns. It effectively becomes a tiny Schrader valve. Most commonly fitted to very cheap childrens pavement bikes in Europe (and Generally those by the mass italian manufacturer Vivo). Why ? I've no idea, as they are not available in the UK other than as O.E. it almost always involves drilling out the (steel) rims and fitting Schrader valved tubes at the first puncture........
More on topic for the list - Schwalbe do excellent quality 26 x 1.1/4" & 1.3/8" woods valved tubes....... -- Bob Reid Stonehaven Scotland
The Flying Scot Website - http://freespace.virgin.net/