I've just been informed of a great website about String Format explanation with some good examples: http://www.csharp-examples.net/string-format-double/
The .NET Framework provides extensive formatting support, which is described in greater detail in the following formatting topics:
For more information about numeric format specifiers, see Standard Numeric Format Strings and Custom Numeric Format Strings.
For more information about formatting, see Formatting Types and Formatting Overview.
And: http://msdn.microsoft.com/en-us/library/system.decimal.tostring.aspx