Secret Trainer Card Stickers
At the lowest house on Island Four talk to the man inside and do the following:

Hall of Fame Sticker #1:
Beat The Elite Four One Time

Hall of Fame Sticker #2:
Beat The Elite Four Fourty Times

Hall of Fame Sticker #3:
Beat The Elite Four One Hundred Times

Hall of Fame Sticker #4:
Beat The Elite Four Two Hundred Times

Egg Hatching Sticker #1:
Hatch One Egg

Egg Hatching Sticker #2:
Hatch One Hundred Eggs

Egg Hatching Sticker #3:
Hatch Two Hundred Eggs

Egg Hatching Sticker #4:
Hatch Three Hundred Eggs

Winning A Link Battle Sticker #1:
Win One Link Battle

Winning A Link Battle Sticker #2:
Win Twenty Link Battles

Winning A Link Battle Sticker #3:
Win Fifty Link Battles

Winning A Link Battle Sticker #4:
Win One Hundred Link Battles

The National Dex (JP Version):
Go to Pallet Town and see the Professor when you have defeated the Elite Four and have more than 60 Pokemon in the Pokedex. The Professor will give you and Gary the National Dex which enables you to view all 386 Pokemon entries.

Aurora Ticket/Deoxys:
Download the Aurora Ticket at Nintendo Events to be able to go to Birth Island to get Deoxy.

Mystic Ticket/Lugia and Ho-Oh:
Download the Mystic ticket at Nintendo Events to be able to go to Navel Rock to get Lugia and Ho-Oh.

ItemFinder Secrets
In the game there are locations where important people/Pokemon have stood at one point. If you use the Itemfinder on the EXACT spot they stood a special item will be found which is usually very rare. This is the only way to find these items.

Macho Brace:
In Viridian Gym use Itemfinder where Giovanni was.

Sacred Ash:
Navel Rock use Itemfinder where Ho-Oh was.

Soothe Bell:
In the Pokemon Tower use Itemfinder where Mr. Fuji was.

Leftovers:
Near Cycling Road and Silence Bridge use Itemfinder where Snorlax was.

Diploma:
To get the Diploma complete the National Dex by catching all 386 Pokemon.

There are no 'cheats' as such for Pokemon Fire Red. By this I mean no press up, down, left and you'll get soemthing.

But at Super Cheats we have an extensive collection of user submitted hints, questions and answers (members can ask questions too!), and walkthroughs and faqs for Pokemon Fire Red.

Many aspects of the game are on those pages, registered users can ask questions, and if you visit the questions and answers page you'll see that many hundreds of questions have already been asked - and answered! :) Maybe your question has already been posted.

On the questions and answers page there is a search facility where you can search for keywords, so if your question related the Mew, just type Mew in the search box and you'll get all of the questions already asked about Mew.

Further help can also be found on our Fire Red forums.