Pokémon Ruby Tips

Easy Experience
Go to the daycare that is located right of Mauville City. (It's just outside Mauville City. You should see it right when you leave Mauville.) Have the daycare lady raise two of your pokemon. Then go back to Mauville and get an acro bike from the bike shop. (If you don't already have it.) Now go to the desert that you had to use your Go-Goggles for and go to the mudslide that you use your mach bike for. Get on your acro bike and position yourself right in front of the mudslide. Now find an object or some way to hold down the up button on your d-pad. Your character should coninuously move up and down the mudslide. Now just leave the gameboy on and come back in a couple of hours and your two pokemon should be levelled up.

Each time your character moves up the mudslide and then back down is 2 EXP. points. If your wondering how many levels your pokemon will gain it, of course, depends on how much time goes by and how high of a level your pokemon are on.
level 20-30 about 5-6 levels an hour.
level 40-50 about 3-4 levels an hour.
level 50-70 about 2-3 levels an hour. and so on..
The best thing to do is to just leave your gameboy on all night and your pokemon will definetly gain 10 or more levels.
The bad thing about doing this cheat is that it uses a LOT of battery power if you dont have the Gameboy player for gamecube or the Gameboy Avance SP and it would be faster to just level your pokemon up manually. The daycare may also replace moves your pokemon have with new moves they may learn when levelling up which can sometimes be bad. Lastly, you have to pay more money the more your pokemon level up. Well, that's all! Enjoy!