is it a big problems to find somebody's phone number?

Question

don't u feel that i have to design something based on this?

Answer 1

Not if they want you to have it.

Answer 2

www.whitepages.com is an online phone directory that has a reverse lookup as well (if you know the phone number but not the name, and vice versa--know the name but not the number) for people and businesses.

www.infobel.com/teldir (links to worldwide phone directories)
www.anywho.com (AT & T's phone directory online)
www.callwave.com (for cell phone)
www.infospace.com (reverse lookups)
www.numberway.com (worldwide phone directories)