you go to the place that's called only nerds play poptropica
it is located in the black widows lair
He went off to the black widows lair .
You'll need it later on to get into Black Widows' Lair.
go to downtown then to country side and keep walking and there it is
In the Black Widows lair under the floor, but you have to peel back the painting on the second floor of the house you need the key to.
in the lair of black widow
In her secret lair.
When you get close to recovering the stolen painting, she will take you there.
You do this near the end of the game, when you are in the lair of the Black Widow.
You don't, its just something useless in the background you can click on, i suggest you click on the peeling painting, then you find yourself tied up with the same person who framed you, lucky.
The curator is in the Web Browser cafe when you emerge from the lair, but you have to meet her in the museum to receive your Island Medallion.
Later in the game you'll go to the "Black Widow's" lair. That's where you'll use the keycard :)