Special Characters in XML
It is possible to escape special characters in XML (see this answer and this answer) using number notations such as this example:
Joe's Café & Bar ♫
escaped using number notation:
TIP: Use an encoding tool
In order to test conversion and encoding you can use one of the many available online tools, one such example is Coder´s Toolbox for encoding URL values.
Joe's Café & Bar ♫
But in the case of product feeds, you should never need to do this as long as your XML file is UTF-8 encoded and that all fields containing strings are wrapped in CDATA tags.
Please note that for URLs we are more strict and require them to be url encoded properly according to RFC specification.