As with all Pokémon games there are a handful of useful characters dotted throughout the map. Here's how to find them and what they can do for you.

Name Rater

Location: Lavender Town

This eccentric fellow lives south of the Volunteer House and will at no cost judge your Pokémon's nicknames. If they belong to you he'll even let you rename them.

Happiness Checker

Location: Pallet Town

Your rival's sister who gives you a Town Map the first time you meet her. She lives next door to you. If you visit her later on, she'll groom your Pokémon from time to time thus increasing its happiness. She will also give you notes on how much your Pokémon likes you

Statement Values
It couldn't possibly love you any more than it does now. Your Pokemon is happy beyond words. 250+
It looks very happy. 200-249
It's quite friendly with you. Keep being good to it! 150-199
It's warming up to you. Trust must be growing between you. 100-149
It's not quite familiar with you yet. 50-89
I don't like the way it glares at you. Could you try being a little nicer to it? 1-49
Move Deleter

Location: Fuchsia City

This older fellow lives beside the Gym and will remove any attack you wish from your party members, including HMs which cannot be overwritten in any other way. This is a necessary character if you wish to move a Pokémon with an HM from this game into Diamond, Pearl, Platinum, HeartGold or SoulSilver
Move Reminder

Location: Two Island

This older fellow lives beside the Gym and will remove any attack you wish from your party members, including HMs which cannot be overwritten in any other way.