Hi,
you can uninstall it like any other extension:

e.g. go to Extensions->Manage->Manage in the menu
Use the search box to search for "Chameleon"
click next to each of the Chameleon plugins and extension:

Chameleon
Chameleon - Extended Actions
Chameleon - Extended Rules
Chameleon - FLEXIcontent Rules
Chameleon - Hikashop Rules
Chameleon - K2 Rules
Chameleon - VirtueMart Rules
System - Chameleon
System - Chameleon Actions

Then click on the "Uninstall" button at the top.

Cheers,
Stephen