There are a few books out there. I've not been able to find the iPhone 4 for dummies but I did get one called iPhone in easy steps by Drew Provan. It's pretty good and reasonably priced. Check on
Amazon if you're not in a hurry!
Also I'm working on a list of phrases and terms that people use here frequently that noobs and rookies like you and me don't always understand. I suggested that some sort of Glossary be made and one of the Mods said he'd make a sticky.... so stay tuned