Visual Studio: How to show Overloads in IntelliSense?

With your cursor inside the parentheses, use the keyboard shortcut Ctrl-Shift-Space. If you changed the default, this corresponds to Edit.ParameterInfo.

Example:

Ctrl+Shift+Space shows the Edit.ParameterInfo for the selected method, and by selected method I mean the caret must be within the method parentheses.

Here is the Visual Studio 2010 Keybinding Poster.

And for those still using 2008.