In any of the codebehind pages that inherit from the SkinBase class, you can just use
Code:
ThisCustomer.CustomerLevelID
to get the integer value representing the customer level id or
Code:
ThisCustomer.CustomerLevelName
to get the string value representing the customer level name (will be blank if the customer is not logged in or a member of the default (Level 0) customer level).
To get this in the xmlpackage, just use
Code:
<xsl:value-of select="/root/Runtime/CustomerLevelID" />
or
Code:
<xsl:value-of select="/root/Runtime/CustomerLevelName" />