If you mean the 8th gym badge, you must first defeat Clair, the gym leader. After you defeat her, you must go behind the gym, into the Dragon's Den. When you navigate yourself to the building inside, talk to the elder. Answer the questions in a very nice and goody-two shoes manner, and Clair will come in and painfully give you the badge.
same way you get in
u get it when u defeat gym 8
when you beat 8 gym leaders professor elm gives you one.
To face the elite four at indigo plateu
Go to the Kanto region and try to beat their 8 gym leaders.
seafoam islands; 15th gym
In the gym!
in his gym
no
well there are 8 gyms so you have to go to cinnabar and talk to blue then he should be at the viridian gym
The fourth gym leader in Pokemon Soul Silver is in Ecruteak City.
I think it's about 32. ITS 16. 8 FROM JHOTO AND 8 FROM KANTO