I think I have found a pretty good information leaflet on wheezy infants and children here.
When Should I Worry is an online patient information leaflet for parents concerned about their unwell child.
Healthier Together is another good site for both healthcare professionals and parents.
The PIERNetwork is a site for professionals but has an awful lot of good stuff if you are interested. For example, the list of guidelines is extensive and thorough. Well worth a look.