Assuming ios 5, If you back up to iCloud then you don't need a pc and won't loose your iPhone data, but be aware any music or films not downloaded via iTunes will not transfer unless you buy an extension and perhaps a bigger file size.
Contacts in M$ outlook or Outlook Express can be exported to a file and imported to the new machine using a USB finger, or even imported to google, hotmail etc. Those sites give you instructions and the advantage is they are then available to you from anywhere in the world where you can access a pc or iPad etc.