current default string encoding

[Luc Saffre]

Hello,

excerpt from Python 2.2 Library Reference, Section 2.2 Built-in Types:

encode([encoding[,errors]]) 
Return an encoded version of the string. Default encoding is the
current default string encoding. errors may be given to set a
different error handling scheme. The default for errors is 'strict',
meaning that encoding errors raise a ValueError. Other possible values
are 'ignore' and 'replace'. New in version 2.0. 


Question: 
How or where is this current default string encoding defined? Can i
change it during run-time?