Ctrl+K,Ctrl+R opens the Object Browser in Visual Studio 2010. Find what you're looking for by searching and browsing and filtering the results. See also Ctrl+Alt+J. ^K ^R
is better because it puts your caret right in the search box, ready to type your new search, even when the Object Browser is already open.
Set the Browse list on the top left to where you want to look to get started. From there you can use the search box (2nd text box from the top, goes all the way across the Object Browser window) or you can just go through everything from the tree on the left. Searches are temporary but the "selected components" set by the Browse list persists. Set a custom set with the little "..." button just to the right of the list.
Objects, packages, namespaces, types, etc. on the left; fields, methods, constants, etc. on the top right, docstrings on the lower right.
The display mode of a pane can be changed by right-clicking in the empty space of the window; tree organized by assembly/container or by namespace and other preferences.
Items can be right-clicked to find, copy and filter.
For keyboard navigation, use Ctrl+K,Ctrl+R from anywhere to start a new search, Enter to execute the search you just typed or pasted and Ctrl+F6 to make the Object Browser close. ALT+<-- to go back and ALT+--> to go forward through the search history. More can be set; search for "ObjectBrowser" in the keyboard shortcut config.
If the key shortcuts above don't work, Object Browser should be in the View menu somewhere with a different shortcut. If all else fails, search for "ObjectBrowser" under Tools->Options->Environment->Keyboard->"Show commands containing".