You probably want to look at Collaboraid's Internationalization Effort over at
http://
www.collaboraid.biz/extranet/i18n/blog/.
In general, if you want to return different ADPs, make sure to set up "index.tcl"
because that will be sourced first. Then, use whatever logic you need in
index.tcl to return the right ADP file, which you can do using:
ad_return_template <template_name>
where <template_name> is index_e or index_s.