Where is Eclipse Marketplace in Android SDK
the marketplace could be manually installed:
help->install new software->choose Juno->general purpose software-> Marketplace client
Try this...
Go to Help,
Then click Install New Software,
Press Add,
Name = "your option" and Location = "http://download.eclipse.org/releases/juno" then press OK,
Select all press Next,
Select general purpose software
Select Marketplace client from the extracted checklist items then press next.
Accept all the terms and conditions then press install.
Then restart the ADT.
To install Marketplace on android adt
Can you follow this path :-
Help -> install new software -> choose Juno -> general purpose software -> Marketplace client