In the main screen of OSMDROID's webpage can be saw the use of bubble of information but I don't know how implement this funcionality. I searched how do it in the official documentation, internet and stackoverflow but I don't find anything.
Does this functionality available in the library or just is part of OSMViewer?
The source code for the viewer program is on Google Code so you can see how they've done everything: http://code.google.com/p/osmdroid/source/browse/#svn%2Ftrunk%2FOpenStreetMapViewer
I think that what you're looking for is a ItemizedOverlayWithFocus, used here: http://code.google.com/p/osmdroid/source/browse/trunk/OpenStreetMapViewer/src/org/osmdroid/samples/SampleWithMinimapItemizedoverlayWithFocus.java