How to get inside the silph.co?

Defeat the rockets in Celadon Game Corner (and Giovanni). Then, get the Silph Scope. Go through Pokemon Mansion and defeat the rockets on the top. Save Mr. Fuji, he'll give you the PokeFlute. By now, Silph Co. Will be open. To get to Saffron, go back to Celadon and go inside the big building (Celadon Mansion). In the 1st floor, talk to the old lady and she'll give you the Tea. Go to one of the gates and he'll take the Tea. He'll allow you to enter Saffron. The rocket that's guarding it will move over because it's *taking a snooze*.

Uh, walk into the door of the big building in the middle of Saffron City? I'm guessing you're looking for the Card Key though, so go to the 5th floor via elevator, walk out and go to YOUR right(like if you walked out of it for real) and encounter a traner with a Magneton, Magnamite, Weezing & Koffing. Keep going down (south) that hallway until you find another trainer with a Machop and a Machamp. Now take that teleporting device 2 times to get past that trainer. Go East(or right I guess depending on perspective)and the item halfway down the hall will be the Card Key. Go back down to the 3rd floor and then figure it out from there, it's not too tough, just a lot of teleporters. There's a bunch of good stuff in there, so try to explore all of the floors.

You must first go to the celadon game corner....battle the team rocket grunt in front of the poster...after you beat him...go read the poster...it will say ''what a secret switch''.....then stair's will be opened...defeat all Team Rocket there and obtain the Silp. Scope by defeating Giovani..after that you can gain access to Silp. Co Building.

Rescue Mr. Fuji in Pok�mon Tower (sort of) and get the Pok� Flute.

Just rescue Mr Fuji in the Pokemon tower and receive poke flute. Then you can get snorlax ( or defeat it) on route 12 then the rocket grunt infront of the place will be sleeping so just go on through