Hi
One of the single most valuable cell phone resources I've run across is a powerful, effective cell phone number directory that lets you look ip people by name and find their cell phone number. There are a few 'wannabe' sites out there that do a dismal job of it, but one has been around since 2000 and today is the largest databse of cell phone numbers publically available anywhere. It's opt-in only so necessarily incomplete, but it it is international, available in eight languages, and completely free to search (as well as offering free listings of course), so what's not to like? There's even a responsive version (at the same address) that automatically adapts it's layout to being accessed on your mobile phone screen. Here's the details:

MobilePhoneNumber.com

So if there's somebody you need to find, lookup their personal cell phone number right here.