Mac users have it easy since Address Book does exactly this (although I am not exactly sure whether it will pass without iTunes sync).
For windows just use CopyTrans Contacts - I have been using it on my jailbroken iPhone and by non-jailbroken iPad and works fine for adding/editing contacts - no iTunes required.
I am looking for a program to Transfer/Restore iPhone Contacts to/from my PC,
without using iTunes.
I have never succesfully installed iTunes on my SonyLaptop. Install always fails. So to heck with it.