I want to synch my iphone with a different computer than I have in the past. Apparently, you can only synch with one computer. When I go to synch it says something like, this will erase what is on your iphone now and replace it with the synched material. That is okay with me, provided nothing happens to what I have in "contacts." That is actually synched with my work computer. Is it only itunes music, audiobooks, etc. that is affected? Are my contacts safe?