Just load "MongoTalk" from config browser in Pharo 4, run you Mongo database and then use Spotter to enter/search a database name.
When Mongo is running locally you can directly use spotter to browse Mongo databases, included collections and documents.
If Mongo is not running on localhost you can also switch the default
Mongo default: (Mongo host: 'myserver' port: 1234)
to browse remotely.