Is nearby a website that I can enter my phone contacts, consequently download them to my iphone?
Answers:
What do you expect? I have an iphone. Why dont you a short time ago enter them in your phone. Or even simpler...why not just use Windows Contact (Vista) or Windows Address Book (XP) and enter them surrounded by there, later sync? No internet required!
P.S. I assume you're on Windows, otherwise you wouldn't be asking this question, since Mac already have an Address Book in the dock...but Windows's is invisible in the Start Menu